LONDON (AFP) - Former British foreign secretary Jack Straw has said he would step down as a member of parliament at the 2015 general election.

Straw, 67, was foreign secretary under prime minister Tony Blair as Britain went to war in Iraq in 2003.

The lawmaker for the Labour Party, now in opposition, has served continuously as an MP since 1979, representing the town of Blackburn in northwest England.

He was one of only three people to serve in the Cabinet throughout the Labour administrations of 1997 to 2010 under Blair and Gordon Brown.

Straw said that in making his decision there were three issues he had to face.

"First, that I couldn't go on forever as the town's MP," he said on Friday.

"Second, that whether I stood down in 2015, or in 2020, or whenever, it would be a terrible wrench.

"Third, that whilst I am as certain as anyone can be that I'd have the energy to continue at the pace necessary for three or four years, I couldn't guarantee that I could keep going at that pace right into my mid-70s."

Labour leader Ed Miliband hinted that Straw might be offered a seat in the unelected upper House of Lords, saying he "will continue to serve our country in many different ways".

A former president of the National Union of Students, Straw was a lawyer by training.

He served as interior minister from 1997 to 2001, infuriating many on the Labour left by blocking the extradition of Chilean dictator Augusto Pinochet to face trial in Spain after his arrest in London, and eventually allowed him to return home on health grounds.

Moving from home secretary to foreign secretary from 2001 to 2006, he was a staunch supporter of Blair's decision to join the invasion of Iraq.

He then became leader of the lower House of Commons - the person responsible for arranging government business, then justice secretary and lord chancellor, the first non-peer since the 16th century to be appointed to the latter role.

He ran Brown's campaign for the Labour leadership after Blair stood down in 2007.