US 'used its Yorkshire base to spy on Merkel' claims whistleblower RAF Menwith Hill, run by NSA, is the biggest surveillance facility in Europe Claims by US whistleblower J. Kirk Wiebe dragged Britain into scandal Base works closely with Britain's own top-secret listening station, GCHQ By Caroline Graham and Robert Verkaik The United States used a British spy base to listen in on the phone calls of Angela Merkel and 35 other world leaders, it was claimed last night. RAF Menwith Hill in North Yorkshire, which is run by America's National Security Agency (NSA), is the biggest surveillance and interception facility in Europe. The base analyses satellite signals as well as mobile phone and electronic data from private individuals, governments and corporations. Concern: RAF Menwith Hill in Yorkshire has now been dragged inot the intelligence scandal. Menwith Hill, which has 33 distinctive golf ball-shaped 'radomes' to house satellite dishes, was effectively handed over to the Americans in the 1950s in recognition of the important intelligence-sharing relationship between the two countries Last week it was reported that American spies had been listening in on the phone conversations of dozens of world leaders. Claim: NSA whistleblower J Kirk Wiebe implicated the British base The allegations led Mrs Merkel to call Barack Obama and ask him to account for his agents" actions. Now fresh claims by US whistleblower J. Kirk Wiebe, who worked for the NSA for 30 years, have dragged Britain into the scandal. Mr Wiebe believes US agents used the base to intercept the German leader's phone calls - with the full knowledge of British officials. He told The Mail on Sunday it was likely agents at Menwith Hill "either directly collected the data or would have processed data" from the bugged calls before sending the information back to Washington. Mr Wiebe, who left the NSA in 2001 over fears it was illegally gathering "huge swathes" of electronic data from citizens in the US and globally, said: "If the information didn't come from there, it is almost a certainty that it would have been processed there." He added: "Everything goes through there to be analysed before the information is sent back to Washington." Menwith Hill, which has 33 distinctive golf ball-shaped "radomes" to house satellite dishes, was effectively handed over to the Americans in the 1950s in recognition of the important intelligence-sharing relationship between the two countries. The base works closely with Britain's own top-secret listening station, GCHQ in Cheltenham. Committee: Former Liberal Democrat leader Sir Menzies Campbell, one of the MPs who sits on the committee, said there needed to be a 'robust and easily understood legal system of control'. He told The Mail on Sunday that the current system of regulation was set up before some of the 'far-reaching capabilities of intelligence-gathering' were in existence Any information processed or analysed at Menwith Hill is then sent back to NSA headquarters in Fort Meade, Washington. The Ministry of Defence insists Ministers are "fully briefed on the activities at RAF Menwith Hill." But concerns have long been expressed about the lack of scrutiny US spying operations face when they are carried out on British soil. Responding to calls for greater transparency, the Commons" Intelligence and Security Committee - whose members are among a select group of British politicians with security clearance to visit the site - has promised to review the laws that keep a check on intelligence-gathering by Britain. Former Liberal Democrat leader Sir Menzies Campbell, one of the MPs who sits on the committee, said there needed to be a "robust and easily understood legal system of control." Listening in: Last week it was reported that American spies had been listening in on the phone conversations of dozens of world leaders including Angela Merkal (pictured). The allegations led Mrs Merkel to call Barack Obama and ask him to account for his agents' action He told The Mail on Sunday that the current system of regulation was set up before some of the "far-reaching capabilities of intelligence-gathering" were in existence. Sir Menzies said: "Parliament must therefore be ready to review whether the existing legislation is good enough. When it comes to relations with other countries there is a well-established relationship between the five eyes - the UK, USA, Canada, Australia and New Zealand. Of these relationships, the one between the UK and the US is by far the strongest. But no matter the strength of any relationship, the responsibility for legality and for review must always rest with domestic government. Documents leaked by NSA whistleblower Edward Snowden in June revealed how spies based at Menwith Hill managed to intercept Dmitry Medvedev's calls as the former Russian president visited Britain for the G20 summit in 2009. But Mr Wiebe's claim suggests that the base is used to intercept calls from politicians all over Europe, not just those who are visiting the UK. The Ministry of Defence said: "We do not comment on intelligence matters."