Swiss Spy Warningofficial, it emerged last night.
Security chiefs in the UK have been warned that hugely sensitive information they provided to the NDB, Switzerland’s spy agency, could have been ‘compromised’.
Hundreds of thousands of pages of classified documents were copied by a senior IT technician for the NDB, which he then copied for himself on to portable storage devices carrying them away in a backpack.Swiss officials believe the suspect intended to sell the stolen data and have alerted both MI6 and America’s CIA.
The information was shared between Britain, Switzerland and the United States and the CIA has also been warned about the risk.
The technician, whose name has not been made public, was arrested by Swiss authorities last summer.
He was later released from prison while a criminal investigation by the office of Switzerland's Federal Attorney General continues.
A European security source said it is believed the IT worker became disgruntled when he felt his advice on operating the data systems was not being taken seriously.
The technician downloaded hundreds of thousands, or even millions, of printed pages of classified material from the Swiss intelligence service's servers onto portable hard drives.He then carried them out of government buildings in a backpack.
Investigators now believe warning signs were missed in the months leading to his arrest.
The source said that the suspect became so disgruntled earlier this year that he stopped showing up for work.
He worked for the NDB - or Federal Intelligence Service, which is part of Switzerland's Defense Ministry - for about eight years.
He was described by one source as a ‘very talented’ technician.
The worker also had ‘administrator rights’, which gave him unrestricted access to most or all of the NDB's networks, including those holding vast caches of secret data.
Swiss investigators seized portable storage devices containing the stolen data after they arrested the suspect.
The information was impounded before he had an opportunity to sell it.
However, Swiss investigators could not be positive he did not manage to pass any of the information on before his arrest.
Representatives of U.S. and British intelligence agencies had no immediate response to detailed queries about the case submitted by news agency Reuters.
Swiss Attorney General Michael Lauber and a senior prosecutor, Carolo Bulletti, announced in September they were investigating the data theft and its alleged perpetrator.
A spokeswoman for the attorney general said she was prohibited by law from disclosing the suspect's identity.
A spokesman for the NDB said he could not comment on the investigation.
Security procedures and structures at the NDB, which was set up relatively recently, have now come under increased scrutiny.
It conducts both foreign and domestic intelligence activities for the Swiss government.
Human resources staff are currently linked within the organisation to the agency's information technology division.
This potentially made it difficult or confusing for the subdivision's personnel to investigate themselves, the source said.
Despite warning signs, Swiss news reports say the NDB did not realise something was amiss until the largest Swiss bank, UBS, expressed concern to authorities about a potentially suspicious attempt to set up a new numbered bank account, which then was traced to the NDB technician.
A Swiss parliamentary committee is now conducting its own investigation into the data theft and is expected to report next spring. Investigators are known to be concerned that the NDB lacks investigative powers, such as to search premises or conduct wiretaps, which are widely used by counter-intelligence investigators in other countries.
News of the theft of intelligence data surfaced with Switzerland's reputation for secrecy and discretion in government and financial affairs already under assault.
Swiss authorities have been investigating, and in some cases have charged, whistleblowers and some European government officials for using criminal methods to acquire confidential financial data about suspected tax evaders from Switzerland's traditionally secretive banks.
One source said the CIA and MI6 routinely shared data on counter-terrorism and other issues with the NDB.
The greatest danger would be the leaking of any information which could identify British agents or operations, though there is no suggestion this has happened.