Tag Archive: GCHQ


• 1.8m users targeted by UK agency in six-month period alone
• Optic Nerve program collected Yahoo webcam images in bulk
• Yahoo: ‘A whole new level of violation of our users’ privacy’
• Material included large quantity of sexually explicit images
Yahoo webcam image.

The GCHQ program saved one image every five minutes from the users’ feeds. Photograph: Chris Jackson/Getty Images

Britain’s surveillance agency GCHQ, with aid from the US National Security Agency, intercepted and stored the webcam images of millions of internet users not suspected of wrongdoing, secret documents reveal.

GCHQ files dating between 2008 and 2010 explicitly state that a surveillance program codenamed Optic Nerve collected still images of Yahoo webcam chats in bulk and saved them to agency databases, regardless of whether individual users were an intelligence target or not.

In one six-month period in 2008 alone, the agency collected webcam imagery – including substantial quantities of sexually explicit communications – from more than 1.8 million Yahoo user accounts globally.

Yahoo reacted furiously to the webcam interception when approached by the Guardian. The company denied any prior knowledge of the program, accusing the agencies of “a whole new level of violation of our users’ privacy“.

GCHQ does not have the technical means to make sure no images of UK or US citizens are collected and stored by the system, and there are no restrictions under UK law to prevent Americans’ images being accessed by British analysts without an individual warrant.

The documents also chronicle GCHQ‘s sustained struggle to keep the large store of sexually explicit imagery collected by Optic Nerve away from the eyes of its staff, though there is little discussion about the privacy implications of storing this material in the first place.

NSA ragout 4

 

Optic Nerve, the documents provided by NSA whistleblower Edward Snowden show, began as a prototype in 2008 and was still active in 2012, according to an internal GCHQ wiki page accessed that year.

The system, eerily reminiscent of the telescreens evoked in George Orwell’s 1984, was used for experiments in automated facial recognition, to monitor GCHQ‘s existing targets, and to discover new targets of interest. Such searches could be used to try to find terror suspects or criminals making use of multiple, anonymous user IDs.

Rather than collecting webcam chats in their entirety, the program saved one image every five minutes from the users’ feeds, partly to comply with human rights legislation, and also to avoid overloading GCHQ‘s servers. The documents describe these users as “unselected” – intelligence agency parlance for bulk rather than targeted collection.

One document even likened the program’s “bulk access to Yahoo webcam images/events” to a massive digital police mugbook of previously arrested individuals.

“Face detection has the potential to aid selection of useful images for ‘mugshots’ or even for face recognition by assessing the angle of the face,” it reads. “The best images are ones where the person is facing the camera with their face upright.”

The agency did make efforts to limit analysts’ ability to see webcam images, restricting bulk searches to metadata only.

However, analysts were shown the faces of people with similar usernames to surveillance targets, potentially dragging in large numbers of innocent people. One document tells agency staff they were allowed to display “webcam images associated with similar Yahoo identifiers to your known target”.

Optic Nerve was based on collecting information from GCHQ‘s huge network of internet cable taps, which was then processed and fed into systems provided by the NSA. Webcam information was fed into NSA’s XKeyscore search tool, and NSA research was used to build the tool which identified Yahoo’s webcam traffic.

Bulk surveillance on Yahoo users was begun, the documents said, because “Yahoo webcam is known to be used by GCHQ targets”.

NSA ragout 3

 

Programs like Optic Nerve, which collect information in bulk from largely anonymous user IDs, are unable to filter out information from UK or US citizens. Unlike the NSA, GCHQ is not required by UK law to “minimize”, or remove, domestic citizens’ information from its databases. However, additional legal authorisations are required before analysts can search for the data of individuals likely to be in the British Isles at the time of the search.

 

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• NSA extracts location, contacts and financial transactions
• ‘Dishfire’ program sweeps up ‘pretty much everything it can’
• GCHQ using database to search metadata from UK numbers

Dishfire presentation on text message collection – key extracts

Texting on BlackBerry mobile phone
The NSA has made extensive use of its text message database to extract information on people under no suspicion of illegal activity. Photograph: Dave Thompson/PA

The National Security Agency has collected almost 200 million text messages a day from across the globe, using them to extract data including location, contact networks and credit card details, according to top-secret documents.

The untargeted collection and storage of SMS messages – including their contacts – is revealed in a joint investigation between the Guardian and the UK’s Channel 4 News based on material provided by NSA whistleblower Edward Snowden.

The documents also reveal the UK spy agency GCHQ has made use of the NSA database to search the metadata of “untargeted and unwarranted” communications belonging to people in the UK.

The NSA program, codenamed Dishfire, collects “pretty much everything it can”, according to GCHQ documents, rather than merely storing the communications of existing surveillance targets.

The NSA has made extensive use of its vast text message database to extract information on people’s travel plans, contact books, financial transactions and more – including of individuals under no suspicion of illegal activity.

An agency presentation from 2011 – subtitled “SMS Text Messages: A Goldmine to Exploit” – reveals the program collected an average of 194 million text messages a day in April of that year. In addition to storing the messages themselves, a further program known as “Prefer” conducted automated analysis on the untargeted communications.

sms1
An NSA presentation from 2011 on the agency’s Dishfire program to collect millions of text messages daily. Photograph: Guardian

The Prefer program uses automated text messages such as missed call alerts or texts sent with international roaming charges to extract information, which the agency describes as “content-derived metadata”, and explains that “such gems are not in current metadata stores and would enhance current analytics”.

On average, each day the NSA was able to extract:

• More than 5 million missed-call alerts, for use in contact-chaining analysis (working out someone’s social network from who they contact and when)

• Details of 1.6 million border crossings a day, from network roaming alerts

• More than 110,000 names, from electronic business cards, which also included the ability to extract and save images.

• Over 800,000 financial transactions, either through text-to-text payments or linking credit cards to phone users

The agency was also able to extract geolocation data from more than 76,000 text messages a day, including from “requests by people for route info” and “setting up meetings”. Other travel information was obtained from itinerary texts sent by travel companies, even including cancellations and delays to travel plans.

sms5
A slide on the Dishfire program describes the ‘analytic gems’ of collected metadata. Photograph: Guardian

Communications from US phone numbers, the documents suggest, were removed (or “minimized”) from the database – but those of other countries, including the UK, were retained.

The revelation the NSA is collecting and extracting personal information from hundreds of millions of global text messages a day is likely to intensify international pressure on US president Barack Obama, who on Friday is set to give his response to the report of his NSA review panel.

While US attention has focused on whether the NSA’s controversial phone metadata program will be discontinued, the panel also suggested US spy agencies should pay more consideration to the privacy rights of foreigners, and reconsider spying efforts against allied heads of state and diplomats.

In a statement to the Guardian, a spokeswoman for the NSA said any implication that the agency’s collection was “arbitrary and unconstrained is false”. The agency’s capabilities were directed only against “valid foreign intelligence targets” and were subject to stringent legal safeguards, she said.

The ways in which the UK spy agency GCHQ has made use of the NSA Dishfire database also seems likely to raise questions on the scope of its powers.

While GCHQ is not allowed to search through the content of messages without a warrant – though the contents are stored rather than deleted or “minimized” from the database – the agency’s lawyers decided analysts were able to see who UK phone numbers had been texting, and search for them in the database.

The GCHQ memo sets out in clear terms what the agency’s access to Dishfire allows it to do, before handling how UK communications should be treated. The unique property of Dishfire, it states, is how much untargeted or unselected information it stores.

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Quantum Spying: GCHQ Used Fake LinkedIn Pages to Target Engineers

By SPIEGEL Staff

Officials at LinkedIn say they "would not authorize such activity for any purpose". Zoom

DPA

Officials at LinkedIn say they “would not authorize such activity for any purpose”.

The Belgacom employees probably thought nothing was amiss when they pulled up their profiles on LinkedIn, the professional networking site. The pages looked the way they always did, and they didn’t take any longer than usual to load.

ANZEIGE

The victims didn’t notice that what they were looking at wasn’t the original site but a fake profile with one invisible added feature: a small piece of malware that turned their computers into tools for Britain’s GCHQ intelligence service.

The British intelligence workers had already thoroughly researched the engineers. According to a “top secret” GCHQ presentation disclosed by NSA whistleblower Edward Snowden, they began by identifying employees who worked in network maintenance and security for the partly government-owned Belgian telecommunications company Belgacom.

Then they determined which of the potential targets used LinkedIn or Slashdot.org, a popular news website in the IT community.

‘Quantum Insert’

The computers of these “candidates” were then infected with computer malware that had been placed using infiltration technology the intelligence agency refers to as “Quantum Insert,” which enabled the GCHQ spies to deeply infiltrate the Belgacom internal network and that of its subsidiary BICS, which operates a so-called GRX router system. This type of router is required when users make calls or go online with their mobile phones while abroad.

SPIEGEL’s initial reporting on “Operation Socialist,” a GCHQ program that targeted Belgacom, triggered an investigation by Belgian public prosecutors. In addition, two committees of the European Parliament are investigating an attack by a European Union country on the leading telecommunications provider in another EU member state.

The operation is not an isolated case, but in fact is only one of the signature projects of an elite British Internet intelligence hacking unit working under the auspices of a group called MyNOC, or “My Network Operations Centre.” MyNOCs bring together employees from various GCHQ divisions to cooperate on especially tricky operations. In essence, a MyNOC is a unit that specializes in infiltrating foreign networks. Call it Her Majesty’s hacking service, if you like.

When GCHQ Director Iain Lobban appeared before the British parliament last Thursday, he made an effort to reassure lawmakers alarmed by recent revelations. British intelligence couldn’t exactly stand back and watch the United Kingdom be targeted for industrial espionage, Lobban said. But, he noted, only those whose activities pose a threat to the national or economic security of the United Kingdom could in fact be monitored by his agency.

A Visit from Charles and Camilla

Even members of the royal family occasionally stop by to see what British intelligence is up to. In one photo that appears in a secret document, Charles, the Prince of Wales, and his wife Camilla, the Duchess of Cornwall, are shown listening to a presentation at a MyNOC workstation called “A Space.” The tongue-in-cheek caption reads “Interlopers in A Space.”

The presentation does not indicate the extent to which the royal family is kept abreast of current espionage operations. Their last visit was reportedly about Afghanistan, not Belgium. But the visit had been to the same location where what the secret document described as the “very successful” operation against Belgacom as well as “Operation Wylekey,” also run by a MyNOC unit, had been conducted.

This also relates to an issue that the British have made a focal point of their intelligence-gathering activities: the most comprehensive access possible to worldwide mobile networks, the critical infrastructures for the digital age.

Mobile networks are a blessing and a curse for spies worldwide. Because each major wireless communications company operates its own networks, tapping into them becomes more complex. On the other hand, the mobile multi-use devices in our pockets are a blessing, because they often reveal more personal information than stationary computers, such as the user’s lifestyle habits and location. They can also be transformed into bugging devices that can be activated remotely at any time to listen in on the user’s conversations.

Mobile Phones Become Monitoring Tools

“We can locate, collect, exploit (in real time where appropriate) high value mobile devices & services in a fully converged target centric manner,” a GCHQ document from 2011 states. For years, the British spies have aspired to potentially transform every mobile phone on the planet into a monitoring tool that could be activated at any time.

But the government hackers apparently have to employ workarounds in order to infiltrate the relatively inaccessible mobile phone networks.

According to the presentation, in the case of Belgacom this involved the “exploitation of GRX routers,” from which so-called man-in-the-middle attacks could be launched against the subjects’ smartphones. “This way, an intelligence service could read the entire Internet communications of the target and even track their location or implant spying software on their device,” mobile networks expert Philippe Langlois says of the development. It is an effective approach, Langlois explains, since there are several hundred wireless companies, but only about two dozen GRX providers worldwide.

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Without their knowledge or permission, the National Security Agency has broken into the global data centers of Yahoo! and Google, the Washington Post is reporting on Wednesday.

In a report that terms the specific NSA surveillance program as “unusually aggressive,” the newspaper claims that leaked documents provided by whistleblower Edward Snowden show how the operation, codenamed MUSCULAR, allowed the agency to access the “cloud networks” of the two internet giants and “collect at will from among hundreds of millions of user accounts, many of them belonging to Americans.”

Two engineers with close ties to Google exploded in profanity when they saw the leaked drawing from the NSA: “I hope you publish this,” one of them said.

“The NSA does not keep everything it collects,” the Post reports, “but it keeps a lot.”

Though the stream of information generated by the Snowden leaks seems endless, these latest revelations come amid growing concern both in the U.S. and abroad about the unrivaled power of the NSA when it comes to accessing information that was otherwise thought protected.

In this case, it is the internet giants themselves who seem most caught off guard over the revelations. Since the Snowden leaks first began, these companies (along with others) have been criticized for allowing the NSA specific kinds of access to their customer data.  As the Post reports, however, disclosure of the MUSCULAR program becomes “especially striking,”

because the NSA, under a separate program known as PRISM, has front-door access to Google and Yahoo user accounts through a court-approved process.

The MUSCULAR project appears to be an unusually aggressive use of NSA tradecraft against flagship American companies. The agency is built for high-tech spying, with a wide range of digital tools, but it has not been known to use them routinely against U.S. companies.

When asked by the Post if they were aware of the program, both Yahoo! and Google adamantly said they did not know and expressed deep concern—anger, in fact—that the NSA had possibly infiltrated their private, highly secure, “cloud” networks.

As the Post explains:

In order for the data centers to operate effectively, they synchronize high volumes of information about account holders. Yahoo’s internal network, for example, sometimes transmits entire e-mail archives — years of messages and attachments — from one data center to another.

Tapping the Google and Yahoo clouds allows the NSA to intercept communications in real time and to take “a retrospective look at target activity,” according to one internal NSA document.

In order to obtain free access to data center traffic, the NSA had to circumvent gold standard security measures. Google “goes to great lengths to protect the data and intellectual property in these centers,” according to one of the company’s blog posts, with tightly audited access controls, heat sensitive cameras, round-the-clock guards and biometric verification of identities.

Google and Yahoo also pay for premium data links, designed to be faster, more reliable and more secure. In recent years, each of them is said to have bought or leased thousands of miles of fiber optic cables for their own exclusive use. They had reason to think, insiders said, that their private, internal networks were safe from prying eyes.

In an NSA presentation slide on “Google Cloud Exploitation,” however, a sketch shows where the “Public Internet” meets the internal “Google Cloud” where their data resides. In hand-printed letters, the drawing notes that encryption is “added and removed here!” The artist adds a smiley face, a cheeky celebration of victory over Google security.

Two engineers with close ties to Google exploded in profanity when they saw the drawing. “I hope you publish this,” one of them said.

Whether those in the outraged public will find sympathy with the likes of Google and Yahoo!, the exposure of MUSCULAR shows the degree to which online data—even that which was thought to be more secure—is susceptible to the reach of the NSA.

One of the other key takeaways from the Post reporting is how this particular program seemed to target communication hubs and data centers located outside of the U.S., showing that legal requirements, though clearly not effective overall, certainly have an impact on the manner in which the NSA operates. Again, from the report:

Intercepting communications overseas has clear advantages for the NSA, with looser restrictions and less oversight. NSA documents about the effort refer directly to “full take,” “bulk access” and “high volume” operations on Yahoo and Google networks. Such large-scale collection of Internet content would be illegal in the United States, but the operations take place overseas, where the NSA is allowed to presume that anyone using a foreign data link is a foreigner.

Outside U.S. territory, statutory restrictions on surveillance seldom apply and the Foreign Intelligence Surveillance Court has no jurisdiction. Senate Intelligence Committee Chairwoman Dianne Feinstein has acknowledged that Congress conducts little oversight of intelligence-gathering under the presidential authority of Executive Order 12333 , which defines the basic powers and responsibilities of the intelligence agencies.

John Schindler, a former NSA chief analyst and frequent defender who teaches at the Naval War College, said it was obvious why the agency would prefer to avoid restrictions where it can.

“Look, NSA has platoons of lawyers and their entire job is figuring out how to stay within the law and maximize collection by exploiting every loophole,” he said. “It’s fair to say the rules are less restrictive under Executive Order 12333 than they are under FISA.”

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Snowden leak: NSA secretly accessed Yahoo, Google data centers to collect information

 

Published time: October 30, 2013 16:36
Edited time: October 30, 2013 17:58

Google data center

Google data center

Despite having front-door access to communications transmitted across the biggest Internet companies on Earth, the National Security Agency has been secretly tapping into the two largest online entities in the world, new leaked documents reveal.

Those documents, supplied by former NSA contractor Edward Snowden and obtained by the Washington Post, suggest that the US intelligence agency and its British counterpart have compromised data passed through the computers of Google and Yahoo, the two biggest companies in the world with regards to overall Internet traffic, and in turn allowed those country’s governments and likely their allies access to hundreds of millions of user accounts from individuals around the world.

From undisclosed interception points, the NSA and GCHQ are copying entire data flows across fiber-optic cables that carry information between the data centers of the Silicon Valley giants,” the Post’s Barton Gellman and Ashkan Soltani reported on Wednesday.

The document providing evidence of such was among the trove of files supplied by Mr. Snowden and is dated January 9, 2013, making it among the most recent top-secret files attributed to the 30-year-old whistleblower.

Gen. Keith Alexander, the head of the NSA, told reporters Wednesday afternoon, “I don’t know what the report is,” according to Politico, and said his agency is “not authorized” to tap into Silicon Valley companies. When asked if the NSA tapped into the data centers, Alexander said, “Not to my knowledge.”

 

Director of the National Security Agency Gen. Keith Alexander (AFP Photo / Alex Wong)

Director of the National Security Agency Gen. Keith Alexander (AFP Photo / Alex Wong)

Earlier this year, separate documentation supplied by Mr. Snowden disclosed evidence of PRISM, an NSA-operated program that the intelligence company conducted to target the users of Microsoft, Google, Yahoo, Facebook, PalTalk, YouTube, Skype, AOL and Apple services. When that program was disclosed by the Guardian newspaper in June, reporters there said it allowed the NSA to “collect material including search history, the content of emails, file transfers and live chats” while having direct access to the companies’ servers, at times with the “assistance of communication providers in the US.”

According to the latest leak, the NSA and Britain’s Government Communications Headquarters are conducting similar operations targeting the users of at least two of these companies, although this time under utmost secrecy.

The infiltration is especially striking because the NSA, under a separate program known as PRISM, has front-door access to Google and Yahoo user accounts through a court-approved process,” the Post noted.

And while top-brass in the US intelligence community defended PRISM and said it did not target American Internet users, the newest program — codenamed MUSCULAR — sweeps up data pertaining to the accounts of many Americans, the Post acknowledged.

The MUSCULAR program, according to Wednesday’s leak, involves a process in which the NSA and GCHQ intercept communications overseas, where lax restrictions and oversight allow the agencies access to intelligence with ease.

NSA documents about the effort refer directly to ‘full take,’ ‘bulk access’ and ‘high volume’ operations on Yahoo and Google networks,” the Post reported. “Such large-scale collection of Internet content would be illegal in the United States, but the operations take place overseas, where the NSA is allowed to presume that anyone using a foreign data link is a foreigner.”

 

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Ex-MI6 deputy chief plays down damage caused by Snowden leaks

Nigel Inkster’s comments contrast with claims made by officials that disclosures have seriously damaged UK security

Edward Snowden

Inkster said the leaks by Edward Snowden (pictured) had probably not told those most interested in the activities of the NSA and GCHQ ‘very much they didn’t already know or could have inferred’. Photograph: AP

A former senior British secret intelligence officer on Thursday played down any potential damage done by the leaks to the Guardian of the spying activities of GCHQ and America’s National Security Agency, apparently contradicting claims made by UK security chiefs.

The leaks, by former NSA contractor Edward Snowden were “very embarrassing, uncomfortable, and unfortunate”, Nigel Inkster, former deputy chief of MI6, said.

While Inkster said it was too early to draw any definite conclusions about the impact of the leaks, he added:

“I sense that those most interested in the activities of the NSA and GCHQ have not been told very much they didn’t know already or could have inferred.”

Al-Qaida leaders in the tribal areas of Pakistan had been “in the dark” for some time – in the sense that they had not used any form of electronic media that would “illuminate” their whereabouts, Inkster said. He was referring to counter measures they had taken to avoid detection by western intelligence agencies.

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Exclusive: NSA pays £100m in secret funding for GCHQ

• Secret payments revealed in leaks by Edward Snowden
• GCHQ expected to ‘pull its weight’ for Americans
• Weaker regulation of British spies ‘a selling point’ for NSA

GCHQ's site in Bude, Cornwall

The NSA paid £15.5m towards redevelopments at GCHQ’s site in Bude, north Cornwall, which intercepts communications from the transatlantic cables that carry internet traffic. Photograph: Kieran Doherty/Reuters

The US government has paid at least £100m to the UK spy agency GCHQ over the last three years to secure access to and influence over Britain’s intelligence gathering programmes.

The top secret payments are set out in documents which make clear that the Americans expect a return on the investment, and that GCHQ has to work hard to meet their demands. “GCHQ must pull its weight and be seen to pull its weight,” a GCHQ strategy briefing said.

The funding underlines the closeness of the relationship between GCHQ and its US equivalent, the National Security Agency. But it will raise fears about the hold Washington has over the UK’s biggest and most important intelligence agency, and whether Britain’s dependency on the NSA has become too great.

In one revealing document from 2010, GCHQ acknowledged that the US had “raised a number of issues with regards to meeting NSA‘s minimum expectations”. It said GCHQ “still remains short of the full NSA ask”.

Ministers have denied that GCHQ does the NSA‘s “dirty work”, but in the documents GCHQ describes Britain’s surveillance laws and regulatory regime as a “selling point” for the Americans.

The papers are the latest to emerge from the cache leaked by the American whistleblower Edward Snowden, the former NSA contractor who has railed at the reach of the US and UK intelligence agencies.

Snowden warned about the relationship between the NSA and GCHQ, saying the organisations have been jointly responsible for developing techniques that allow the mass harvesting and analysis of internet traffic. “It’s not just a US problem,” he said. “They are worse than the US.”

As well as the payments, the documents seen by the Guardian reveal:

GCHQ is pouring money into efforts to gather personal information from mobile phones and apps, and has said it wants to be able to “exploit any phone, anywhere, any time”.

• Some GCHQ staff working on one sensitive programme expressed concern about “the morality and ethics of their operational work, particularly given the level of deception involved”.

• The amount of personal data available to GCHQ from internet and mobile traffic has increased by 7,000% in the past five years – but 60% of all Britain’s refined intelligence still appears to come from the NSA.

GCHQ blames China and Russia for the vast majority of cyber-attacks against the UK and is now working with the NSA to provide the British and US militaries with a cyberwarfare capability.

The details of the NSA payments, and the influence the US has over Britain, are set out in GCHQ‘s annual “investment portfolios”. The papers show that the NSA gave GCHQ £22.9m in 2009. The following year the NSA’s contribution increased to £39.9m, which included £4m to support GCHQ’s work for Nato forces in Afghanistan, and £17.2m for the agency’s Mastering the Internet project, which gathers and stores vast amounts of “raw” information ready for analysis.

 

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Wars and Rumors of War

UK support for US drones in Pakistan may be war crime, court is told

Lawyers for Pakistani man whose father was killed by drone strike seek to have sharing of UK intelligence declared unlawful

A US Predator unmanned drone armed with a missile

A US Predator drone armed with a missile: lawyers are seeking permission for a full judicial review of the lawfulness of any British assistance for the US drone programme. Photograph: Massoud Hossaini/AFP/Getty Images

The British government’s support for US drone operations over Pakistan may involve acts of assisting murder or even war crimes, the high court heard on Tuesday.

In the first serious legal challenge in the English courts to the drones campaign, lawyers for a young Pakistani man whose father was killed by a strike from an unmanned aircraft are seeking to have the sharing of UK locational intelligence declared unlawful.

Noor Khan, 27, is said to live in constant fear of a repeat of the attack in North Waziristan in March last year that killed more than 40 other people, who are said to have gathered to discuss a local mining dispute.

The British government has declined to state whether or not its signals intelligence agency GCHQ passes information in support of the CIA drone operations over Pakistan, although the court heard that media reports suggest that it does.

The case opened as the RAF confirmed that it is to double the number of its own drones flying combat and surveillance operations over Afghanistan. The five additional aircraft will be operated from the UK for the first time, rather than the US. The UK’s existing Reaper drones, which are used to target suspected insurgents in Helmand province, have been operated from Creech air force base in Nevada because the RAF has not had the capability to fly them from Britain.

Martin Chamberlain, counsel for Khan, said that a newspaper article in 2010 had reported that GCHQ was using telephone intercepts to provide the US authorities with locational intelligence on leading militants in Afghanistan and Pakistan. The report suggested that the Cheltenham-based agency was proud of this work, which was said to be “in strict accordance with the law”.

On the contrary, Chamberlain said, any GCHQ official who passed locational intelligence to the CIA knowing or believing that it could be used to facilitate a drone strike would be committing a serious criminal offence.

“The participation of a UK intelligence official in US drone strikes, by passing intelligence, may amount to the offence of encouraging or assisting murder,” he said. Alternatively, it could amount to a war crime or a crime against humanity, he added.

Chamberlain said that no GCHQ official would be able to mount a defence of combat immunity, but added that there was no wish in this case to convict any individual of a criminal offence. Rather, Khan was seeking a declaration by the civil courts that such intelligence-sharing is unlawful.

Between June 2004 and September this year, according to research by the Bureau of Investigative Journalism, drone strikes killed between 2,562 and 3,325 people in Pakistan, of whom between 474 and 881 were civilians, including 176 children.

With the number of drone strikes increasing sharply under the Obama administration, the London case is one of several being brought by legal activists around the world in an attempt to challenge their legality of the programme.

In Pakistan, lawyers and human rights activists are mounting two separate court claims: one is intended to trigger a criminal investigation into the actions of two former CIA officials, while the second is seeking a declaration that the strikes amount to acts of war, in order to pressurise the Pakistani air force into shooting down drones operating in the country’s airspace.

During the two-day hearing in London, lawyers for Khan are seeking permission for a full judicial review of the lawfulness of any British assistance for the US drone programme.

Lawyers for William Hague, the foreign secretary, say not only that they will neither confirm nor deny any intelligence-sharing activities in support of drone operations, but that it would be “prejudicial to the national interest” for them even to explain their understanding of the legal basis for any such activities.

For Khan and his lawyers to succeed, they say, the court would need to be satisfied that there is no international armed conflict in Pakistan, with the result that anyone involved in drone strikes was not immune from the criminal law, and that there had been no tacit approval for the strikes from the Pakistan government – another matter that the British government will neither confirm nor deny.

The court would also need to consider, and reject, the US government’s own legal position: that drone strikes are acts of self-defence. It would also need to be satisfied that the handing over of intelligence amounted to participation in hostilities.

The government also says that Khan’s claim would have a “significant impact” on the conduct of the UK’s relations with both the US and Pakistan in an “acutely controversial, sensitive and important” area, and also impact on relations between the US and Pakistan.

The case continues.