A spy in Speedos: Wife blows cover of MI6 chief on Facebook

Lib Dems call for inquiry into leak of personal details on social networking site

Opposition parties yesterday demanded an inquiry into how personal details about the head of MI6, Sir John Sawers, were allowed to be left on Facebook.

The wife of the newly appointed "C" had posted family photographs, information about the location of their home and the whereabouts of their three children and Sir John's parents. She had not asked for privacy protection on her account, leaving it open for millions of users in the open access "London" network to see the entries.

Lady Shelley Sawers also revealed the couple's friendship with senior diplomats and actors, one of whom is a leading character in The Archers. She also disclosed that Sir John's brother-in-law – who holidayed with him last month – is an associate of the convicted Holocaust-denying historian David Irving.

The material was deleted from the internet after a Sunday newspaper contacted the Foreign Office. The Foreign Secretary David Miliband insisted yesterday that the Facebook entry was not a serious security breach.

"It is not a state secret that he wears Speedo swimming trunks, for goodness' sake, let's grow up," he said.

However, the Liberal Democrat foreign affairs spokesman Edward Davey said: "We would be negligent if there wasn't an internal inquiry into the security implications, not just in relation to MI6 but to Sir John and his family. We need to be reassured that there is nothing we need to worry about."

Conservative MP Patrick Mercer, chairman of the Commons' counter-terrorism sub-committee, added: "A great deal of taxpayers' money has been spent making sure that he and his family are protected from security compromises. Well, it doesn't seem to be very relevant anymore, does it?" In 1999 the address of Sir Richard Dearlove, head of MI6, was leaked, as was Stella Rimington's, chief of MI5, in 1991.