Rebel spy to stand against Blair

Mr Shayler, jailed for six months in 2002 for revealing official secrets, will run in Mr Blair's Sedgefield constituency.

The ex-MI5 officer said he would campaign on two anti-war issues and on Mr Blair's ''attacks on democratic rights over the last eight years''.

Mr Shayler, a former counter-terrorism specialist, claimed the Prime Minister's backing for the Iraq war had put Britons at greater risk from terrorism.

He said: ''If we can encourage a large protest vote in Sedgefield, it would send a clear message to the politicians of this country that the people have had enough of autocratic leaders who fail to represent their constituents.

''Between 15,000 and 100,000 innocent people have died in Iraq - not in defence of our liberty and security but on the whim of an ill-informed Prime Minister who boasted to Parliament that he had not checked the detail of the now infamous 45-minute claim, which has since been found to be unreliable.

''Our democracy is in crisis and unless we act now there will be no democracy left worth fighting for in five years' time.''

He added: ''Who knows, if things go right, the people of Britain might again be dancing in the streets over another 'Portillo moment'.''

Mr Shayler said he would ''represent neither left nor right'' and campaign on Mr Blair's ''credibility and ability to lead in the light of his lies over the war''.

He would also highlight the premier's ''uncritical support of the illegal invasion of Iraq'', he said.

Mr Shayler, 39, who was born in the neighbouring constituency of Middlesbrough, also accused the Prime Minister of being ''a symptom and a cause of Britain's decaying democratic infrastructure''.

He said: ''If Blair were an American or French president, the electorate would have a chance to remove him from power.

''As things stand in Britain's increasingly undemocratic society, only the people of Sedgefield have the opportunity to vote him out of power.

''They can do so in the full knowledge that they are not simply doing the best for Britain but also the best for humanity and world peace and stability.''

In 1997 Mr Shayler began a series of disclosures which he claimed revealed incompetence and corruption in the intelligence services. He revealed agents tapped former Labour Cabinet minister Peter Mandelson's telephone for three years in the late 1970s because they wrongly feared he was a Soviet agent.

He also disclosed that MI5 had a file on Foreign Secretary Jack Straw because it was concerned about his involvement with left-wing politics as president of the National Union of Students from 1969 to 1971, and had also kept tabs on Solicitor General Harriet Harman, who once worked as a lawyer for the National Council for Civil Liberties - now called Liberty.

Mr Shayler's most remarkable disclosure was that MI6, the foreign intelligence service, attempted to kill Colonel Muammar Gaddafi by paying an Arab agent £100,000 to place a bomb under the Libyan leader's motorcade in 1996.

The device blew up, killing several innocent bystanders, but Gaddafi escaped unhurt, said Mr Shayler, who worked on MI5's Libyan desk for two years.

An Old Bailey jury found Shayler guilty of three counts of disclosing documents and information to a Sunday newspaper in 1997 in breach of the Official Secrets Act.

Trial judge Mr Justice Moses accused Shayler of ''blinkered arrogance'' and of breaking undertakings he had given before leaving MI5.

He told Shayler he had taken into account the three-and-a-half months he had spent in a French jail while the Government tried unsuccessfully to extradite him.

The judge also accepted Shayler was motivated by a desire to expose what he thought was wrong, and not by money.

Shayler spent three weeks at Belmarsh high-security prison in south east London, where he was given the inmate number HP6007, a lampoon of James Bond's code number, before moving to an open jail.

Convicted prisoners serving a sentence of more than 12 months are disqualified from becoming an MP.