At least six European Union countries in addition to Britain have been colluding with the US over the mass harvesting of personal communications data, according to a former contractor to America's National Security Agency, who said the public should not be "kept in the dark".
Wayne Madsen, a former US navy lieutenant who first worked for the NSA in 1985 and over the next 12 years held several sensitive positions within the agency, names Denmark, the Netherlands, France, Germany, Spain and Italy as having secret deals with the US.
Madsen said the countries had "formal second and third party status" under signal intelligence (sigint) agreements that compels them to hand over data, including mobile phone and internet information to the NSA if requested.
Under international intelligence agreements, confirmed by declassified documents, nations are categorised by the US according to their trust level. The US is first party while the UK, Canada, Australia and New Zealand enjoy second party relationships. Germany and France have third party relationships.
In an interview published last night on the PrivacySurgeon.org blog, Madsen, who has been attacked for holding controversial views on espionage issues, said he had decided to speak out after becoming concerned about the "half story" told by EU politicians regarding the extent of the NSA's activities in Europe.
He said that under the agreements, which were drawn up after the second world war, the "NSA gets the lion's share" of the sigint "take". In return, the third parties to the NSA agreements received "highly sanitised intelligence".
Madsen said he was alarmed at the "sanctimonious outcry" of political leaders who were "feigning shock" about the spying operations while staying silent about their own arrangements with the US, and was particularly concerned that senior German politicians had accused the UK of spying when their country had a similar third-party deal with the NSA.
Although the level of co-operation provided by other European countries to the NSA is not on the same scale as that provided by the UK, the allegations are potentially embarrassing.
"I can't understand how Angela Merkel can keep a straight face, demanding assurances from [Barack] Obama and the UK while Germany has entered into those exact relationships," Madsen said.
The Liberal Democrat MEP Baroness Ludford, a senior member of the European parliament's civil liberties, justice and home affairs committee, said Madsen's allegations confirmed that the entire system for monitoring data interception was a mess, because the EU was unable to intervene in intelligence matters, which remained the exclusive concern of national governments.
"The intelligence agencies are exploiting these contradictions and no one is really holding them to account," Ludford said. "It's terribly undermining to liberal democracy."
Madsen's disclosures have prompted calls for European governments to come clean on their arrangements with the NSA. "There needs to be transparency as to whether or not it is legal for the US or any other security service to interrogate private material," said John Cooper QC, a leading international human rights lawyer. "The problem here is that none of these arrangements has been debated in any democratic arena. I agree with William Hague that sometimes things have to be done in secret, but you don't break the law in secret."
Madsen said all seven European countries and the US have access to the Tat 14 fibre-optic cable network running between Denmark and Germany, the Netherlands, France, the UK and the US, allowing them to intercept vast amounts of data, including phone calls, emails and records of users' access to websites.
He said the public needed to be made aware of the full scale of the communication-sharing arrangements between European countries and the US, which predate the internet and became of strategic importance during the cold war.
The covert relationship between the countries was first outlined in a 2001 report by the European parliament, but their explicit connection with the NSA was not publicised until Madsen decided to speak out.
The European parliament's report followed revelations that the NSA was conducting a global intelligence-gathering operation, known as Echelon, which appears to have established the framework for European member states to collaborate with the US.
"A lot of this information isn't secret, nor is it new," Madsen said. "It's just that governments have chosen to keep the public in the dark about it. The days when they could get away with a conspiracy of silence are over."
This month another former NSA contractor, Edward Snowden, revealed to the Guardian previously undisclosed US programmes to monitor telephone and internet traffic. The NSA is alleged to have shared some of its data, gathered using a specialist tool called Prism, with Britain's GCHQ.