Timeline: Shayler's exile

David Shayler: Has been in France since 1997

As former MI5 officer David Shayler prepares to return from France to the UK, the BBC charts the events during his time in exile.

1997
MI5 officer David Shayler leaves the Intelligence Service after six years.

In August he supplies damning details of MI5 operations in a to the Mail on Sunday newspaper. They include the accusation that the government kept secret files on politicians who are now cabinet ministers. Mr Shayler leaves the UK after the allegations are published.

September: Annie Machon, Mr Shayler's partner, is arrested on arrival at Gatwick airport. She is released after six hours of questioning by Special Branch.

1998
July: He accuses MI5 of failing to react to an impending terrorist attack on the Israeli Embassy in 1994. He also recounts how MI6 officers plotted an assassination attempt against Libyan leader Colonel Gaddafi in 1996.

August: Mr Shayler is arrested in France and held without charge for nearly four months in a Paris jail.

November: The UK Government's attempts to extradite Mr Shayler are rejected by a French court. Mr Shayler says he will not make fresh revelations about the UK's secret services and he attempts to get charges against him dropped.

1999
August: Mr Shayler threatens to reveal more M15 secrets - this time via the internet. He claims that the intelligence information is already stored on his computer and could be released at the push of a button.

September: Mr Shayler compares his treatment with that of Melita Norwood - the elderly spy whose activities had been known about by M15 since 1992. He claims M15 is vindictive against him because he has embarrassed it with his revelations.

December: Mr Shayler launches a campaign to return to the UK.

2000
February: The government issues a writ against Shayler for breaches of confidence, contract and copyright laws on files held by MI5 and the British overseas secret service, MI6.

Shayler also says MI5 files allege that former Beatle John Lennon gave money to the IRA.

March: Mr Shayler's partner, Annie Machon, hands a dossier of documents he has prepared about the alleged Gaddafi assassination plot into the headquarters of Special Branch.

In a bizarre twist police arrest a student at Kingston University in Surrey, after an alleged breach of the official secrets act.

Julie Ann Davies has her college computer searched by police because she has been in contact with David Shayler.

May: To mark his 1,000th day in what he calls "political exile", Shayler plans to mount a crucifix outside the British Embassy in Paris in protest of his treatment by the British Government. He is not allowed to go through with his plans.

July: Mr Shayler's novel, The Organisation, is passed by the government censors. Described as "a gritty thriller about spies, sex and football", he wrote it while living in France.

A High Court judge quashes an order made in March which required the editors of The Guardian and Observer to hand over documents and e-mails sent to them By David Shayler.

The court warned against the making of court disclosure orders against newspapers which might "stifle" investigative journalism unless there was "compelling evidence" the orders were in the public interest.