The father of a Royal Military Policeman killed in Iraq is formally launching his campaign today to unseat Prime Minister Tony Blair in the General Election.

Reg Keys, 52, has already called on the Conservatives and Liberal Democrats not to field candidates in Mr Blair's Sedgefield constituency so that he has a clear run in his attempt to win the seat.

He also asked ex-MI5 officer David Shayler, who has announced he will stand in Sedgefield, to withdraw.

Mr Keys' son, Lance Corporal Tom Keys, 20, was one of six Red Caps killed by an Iraqi mob as they manned a small police station in Al Majar Al Kabir on June 24 2003.

He said his campaign was to achieve ''justice'' for his son, the withdrawal of all British troops from Iraq and to get the Government to release the full legal advice given by Lord Goldsmith on the eve of war.

''I want to hold Tony Blair to account for his deceit,'' Mr Keys said.

''My son Tom believed what he was told, but Blair lied to him, and to all those other soldiers who came home in coffins after fighting in a war that was illegal and immoral.

''The people of Sedgefield need an MP they can trust to speak and act honestly on their behalf. It is time to bring accountability back into politics.''

Mr Keys will be canvassing members of the public in the County Durham constituency, accompanied by Roxy Music star Brian Eno, who is funding his efforts, and former Independent MP Martin Bell.

The former ambulance driver, a founder member of campaign group Military Families Against the War, faces an uphill task to unseat Mr Blair, who had a majority of more than 17,000 at the last election.

:: The declared candidates for Sedgefield include: Tony Blair, Labour; Robert Browne, Liberal Democrats; Jonathan Cockburn, Independent; Reg Keys, Independent; Al Lockwood, Conservative; David Shayler, Independent.