Justice Secretary Jack Straw, one of the ministers touted as a possible replacement for Gordon Brown, said on Tuesday there was no contest for the leadership and backed the prime minister.

"There is no contest, there will be no contest and neither should there be," he told BBC Radio. "We have a powerful leader."

Since Labour's mammoth defeat in the Crewe by-election last week, on top of huge losses in local council elections and poor poll results, media speculation has been rife that some ministers are ready to desert their beleaguered leader.

Straw has been mentioned in the press as a possible caretaker leader if Brown is persuaded to step down.

Foreign Secretary David Miliband and Health Secretary Alan Johnson have also been cited as potential rivals but both spoke out in his favour at the weekend.

Asked whether Brown should name a deputy prime minister - also suggested in the media as a stepping stone to replacing him - Straw said that was up to the prime minister.

"Whether he did or didn't is a matter for him, but the crucial thing for any government is who is in overall charge - the prime minister, and I'm absolutely clear (he is) the man to take us through these difficulties," he said.

Straw said the combination of the global credit crunch and soaring prices were affecting Britain's economy but that Brown would steer the country through.

"We are doing better than other countries and the reason why we have done better than other countries over the last 11 years and we'll get out of this is principally and above all because of Gordon Brown," he added.