The secret-service "whistle-blower" has planned his homecoming, after more than a year in France, to coincide with the implementation of new civil- rights legislation, which he hopes will "massively improve" his case.
At present, Mr Shayler has no legal defence under the Official Secrets Act, which imposes a lifelong duty of confidentiality on those who work in the security services. Any disclosure is illegal, regardless of the public interest, and punishable by two years' imprisonment.
However, he would be able to plead that his revelations were in the public interest and did not breach national security under the Human Rights Act. This received Royal Assent last year and will come into force early in 2000.
The Act incorporates the European Convention on Human Rights and is considered a landmark in human-rights protection because it will provide enforceable civil and political rights in English courts for the first time in British history.
Mr Shayler has also vowed to make further disclosures of alleged incompetence and malpractice in the security services when his case comes to trial. This is likely to embarrass the Government, which has obtained an order preventing him publishing further state secrets.
He has already claimed in a national newspaper that MI6 funded a failed plot to assassinate Colonel Gaddafi, and that the 1994 Israeli-embassy bombing could have been avoided.
His case attracted intense publicity when he was arrested and imprisoned in Paris in August last year, pending an extradition request from Britain.
But the British Government failed to bring him back to this country after a French court ruled that Shayler's actions were politically motivated and therefore he could not be extradited.
Speaking from his home in Paris last week, Mr Shayler said that he was not a traitor and welcomed the opportunity to be vindicated in a court of law. His case is backed by Liberty, the civil rights organisation.
"I want to return to Britain and my chances are massively improved by the Human Rights Act," he said. "Now, the prosecution only has to establish that there has been a breach of the Official Secrets Act.
"There would be so many things I could talk about in open court. It would be a great chance to call the Government's bluff by saying that I am going back to face trial."
He added that the Metropolitan police special branch stated in documents for his extradition that his revelations did not damage national security.
"As far as the Government is concerned, I can rot in hell. I miss my family and friends and I also miss watching football," he said. "I am angry that my image has been tarnished and I want to clear my name."
John Wadham, the director of Liberty and Mr Shayler's lawyer, said he advised his client to return to Britain when the Human Rights Act was implemented because he would have a stronger case: "Under the Official Secrets Act, naming the colour of the carpets at MI5 is an offence. This would not be the case under the new Act."Reuse content