Jack Straw is to step down from frontbench politics after 30 years, he announced yesterday.
The Blackburn MP said he believed Labour needed a “fresh start”.
“I was first appointed to the Labour frontbench in 1980, and then elected to the Shadow Cabinet in 1987,” he told the Press Association. “But now I want the freedom to range more widely over foreign and economic policy.”
He added: “I'll be spending more time on my constituency, and I will be writing a memoir in time.”
Mr Straw said he was not planning to quit as an MP, pointing out that he had been returned with a higher majority at the General Election. “They seem to want me,” he added.
Mr Straw, Gordon Brown and Alistair Darling were the only Labour figures to remain in the Cabinet throughout the party's 13 years in power.
Mr Darling has already indicated he is retiring to the backbenches.
Mr Straw told the Lancashire Telegraph he had been “extraordinarily lucky” with his career.
“My decision (to leave the frontbench) was entirely voluntary. I decided a few months ago, as it seemed we were going into Opposition, that I wouldn't stand.
“The Shadow Cabinet is about offering a fresh start for a party in opposition to present itself to the electorate and I thought 30 years was getting on for enough.”