Specialists in French extradition law said complex legal submissions could drag the process on for two years. But because there is no French equivalent of the Official Secrets Act, the process may be impossible. A large body of case law suggests that a suspect may only be extradited if the alleged crime also exists in France.
There are French laws forbidding the unveiling of specific military and defence secrets but no catch-all Official Secrets Act.
Mr Shayler was arrested in Paris on Saturday evening amid reports that he was about to post MI5 secrets on the internet. He is currently being held at the Prison de la Sante, a reportedly grim prison in Paris. He was due to be visited by consular officials yesterday evening.
Mr Shayler's solicitor, John Wadham, director of the civil rights group Liberty, yesterday repeated his client's intention to fight extradition. He said a French lawyer had been arranged to represent Mr Shayler.
Details of Mr Shayler's arrest remain unclear. He had travelled to Paris from rural France to record an interview for the BBC's Breakfast with Frost programme - due to be broadcast the following morning. He was arrested returning to his hotel after watching a football match and the interview was never recorded.
Yesterday Maitre Simon Foreman, a French lawyer with wide experience of extradition cases, said: "Obviously you can be prosecuted in France if you reveal a state secret. But as far as I understand this case, Mr Shayler is likely to be tried in Britain for infringing principle of state secrecy enshrined in the Official Secrets' Act. No such thing exists in France. We have a tradition of liberty of expression which would make such a law unconstitutional."
He said while there are French laws forbidding the unveiling of specific military and defence secrets there was no catch-all Official Secrets Act.
He added: "At the very least, this is likely to be one of the principle submissions of Shayler's lawyers if they wish to fight the case as vigorously as possible. Whether such a submission would prevent his extradition altogether would remain to be seen."Reuse content