Shayler released from jail

David Shayler was met by his girlfriend outside prison

Ex-MI5 agent David Shayler has vowed to fight to clear his name as he was released from prison early after breaching the Official Secrets Act.

Shayler, 36, was greeted by his girlfriend and brother as he left Ford open prison, near Arundel, West Sussex, on Monday morning after serving less than seven weeks in jail.

He was found guilty on three charges of breaching the act and sentenced and jailed for six months at the beginning of November.

I was imprisoned for telling the truth about the incompetence and illegality in the Security Service

Statement on David Shayler's behalf

In a statement issued by his solicitor, Shayler said he would be appealing to the Court of Appeal and taking his case to the European Court on Human Rights.

Shayler, who is 37 on Tuesday, will spend another seven weeks under the Home Office's home detention curfew scheme.

He will have to observe a curfew from 7pm to 7am and may be electronically tagged.

'Rights violated'

On Shayler's behalf, his solicitor John Wadham, the director of civil rights group Liberty, issued a lengthy statement.

"My conviction and imprisonment violated both my right to a fair trial and my right of freedom of expression and I intend to fight on," he said.

David Shayler spent seven weeks in jail

He will argue at the Court of Appeal that his convictions should be quashed because the trial procedure was "fundamentally flawed and unfair".

Liberty will argue Shayler had to tell the prosecution about his cross-examination and defence in advance and he was unfairly excluded from secret hearings.

The statement continued: "My conviction and sentence were also in breach of freedom of expression - I was imprisoned for telling the truth about the incompetence and illegality in the Security Service.

"The government will have to justify the fact that it is a crime to report a crime when my case comes before the European Court of Human Rights," he said.

He continued they would challenge Labour over its refusal to allow the public interest defence against charges of breaching Official Secrets Act.

Warm welcome

Shayler's girlfriend Annie Machon, a former MI5 officer, was outside prison to meet him along with his brother Phil.

She told BBC News she was overjoyed her boyfriend was out in time for Christmas.

"It is far sooner than we could have ever dreamt of or hoped for.

"The brevity of the sentence does reflects what he did.

"He has not been convicted of treason laws for which he would have got 14 years.

She added: "British people need to know what is going on in their name."

Ms Machon called for protection of whistleblowers, with a new body set up to investigate their allegations.

'Lives put at risk'

Shayler revealed secret documents to the Mail on Sunday newspaper in 1997, arguing he had a public duty to expose malpractice within the security services.

He was initially held at Belmarsh high security prison in south London.

Ahead of his Shayler's release, Mr Wadham, said it was expected his client would return to the island of Osea, off the coast of Essex, where he has been living with Ms Machon.

The former MI5 officer was found guilty of disclosing information, documents and information from telephone taps in breach of the Official Secrets Act.

During the trial, the prosecution said he had potentially placed the lives of dozens of secret agents at risk.

Shayler spent more than three months in prison in France while the government attempted to extradite him.

The former spy copied files including several on Libyan links with the IRA and Soviet funding of the Communist Party of Great Britain, before leaving MI5 in October 1996.

The Mail on Sunday newspaper paid Shayler £40,000.