Shayler has threatened to go public on his website

"As the individual was never read their rights when interviewed by their management and MI5, the prosecution could not go ahead as the authorities had breached the legal procedure," he said.

"Again, this information was never made public," added Mr Shayler.

He suggested that MI5 let the person go rather then risk accusations of incompetence.

Mr Shayler, currently a fugitive in Paris, hopes that the government will grant him immunity from prosecution in return for the names of the individuals concerned.

The authorities want to prosecute Mr Shayler for breaking the Official Secrets Act in an interview he gave to the Mail on Sunday in 1997.

Mr Shayler threatened that if the government was not interested in such a deal, he would go public with the identities by publishing them on his website.

'Astonished' by Norwood's treatment

Mr Shayler said he was "astonished" that no action was taken against one of the spies revealed at the weekend, top KGB agent Melita Norwood, despite MI5 knowing of her activities since 1992.

Tom King: Parliamentary committee to investigate the recent revelations

He said this contrasted with the "persecution" of him by the authorities for attempts to blow the whistle on MI5 malpractice.

He put the MI5's motives down to embarrassment on both counts.

He claimed the service was vindictive against him because he had embarrassed it with his revelations. He also believes no action has been taken against Mrs Norwood because MI5 would have been embarrassed by the subsequent exposure of its incompetence.

"It would have shown they hadn't picked up on this woman and couldn't do their jobs properly," he said.

'Massive impact'

Mr Shayler believes that the weekend's revelations could have a major impact on the way security is conducted in the UK, and on his individual case.

He believes that parliament will demand much greater openness and accountability from the secret services.

And he hopes it could mean that the authorities bring him in from the cold and accept his view that the MI5 culture of secrecy often works against the public interest.

"If the government is not prepared to go forward with prosecutions of traitors it should also look leniently on public-spirited whistle-blowers like myself," he said.

"Perhaps I'll be home for Christmas."