Stephen Byers is one of the most prominent Blairites on the backbenches
Former cabinet minister Stephen Byers has announced he will quit Parliament at the next general election.
The North Tyneside MP said he wanted to "pursue other interests", but insisted he would continue to support Labour.
He has been a fierce critic of Prime Minister Gordon Brown, openly discussing leadership challenges.
Mr Byers, 56, quit as transport secretary in 2002 after an adviser said the 11 September terror attacks made it "a good day to bury bad news".
He told a monthly meeting of the North Tyneside Labour party on Saturday: "By 2010 I will have held elected positions as an MP and councillor for 30 years. That's over half my life and is a long time - especially in modern politics.
"For me this is the right moment to move on in order to pursue other interests and look to fresh challenges."
Mr Byers served as schools minister after Labour won power in 1997, joining the cabinet as chief secretary to the treasury in 1998.
He then moved to trade and industry secretary the same year and became secretary of state for transport, local government and the regions after the 2001 election.
On the backbenches, he was a high-profile Blairite ex-minister pushing for the government to stick to New Labour policies.