Jack Straw has declined to run for Labour's deputy leadership in order to focus on heading Gordon Brown's campaign for the premiership.

It had been rumoured that Mr Straw had cut a deal for the job of Chancellor or another top cabinet post in a Brown-led government.

But the Blackburn MP says that was not the case and he has made the choice, despite being encouraged to run for the deputy leadership by local party members.

Mr Straw said: "The Blackburn party and beyond had been asking me to stand for the deputy leadership.

"I was extremely grateful to them for showing such confidence in me but I felt in the circumstances it would be inappropriate as I could not be both campaign manager and apply for the deputy leadership and that was the choice I made."

The Commons leader insisted the campaign would not start until the Prime Minister had set his departure date. He wants to hang on until after a key EU meeting in June.

The ex-Foreign Secretary and Tony Blair's campaign manager in 1994 announced his new job in an email to fellow Labour MPs and has urged them to back Brown.

He said: "There is absolutely no doubt in my mind that Gordon is the right person."

So far the only contenders in the race apart from Mr Brown are ex-minister Michael Meacher and backbench MP John McDonnell.

Environment Secretary David Milliband has insisted he will not bow to pressure for him to run.

Burnley MP Kitty Ussher said she was "delighted" for Mr Straw.

She added: "I think it's great. It's important we don't start the contest for the leadership now because we have some important elections to deal with first but the fact that it's Jack and he had written to every Labour MP asking them to get involved is a good sign."