What about the minister who had the guts to resign over Iraq?

After a weekend which has seen repeated media calls for Brown to face a proper challenge for the leadership his price has eased further on the betting markets. Just a week ago a £100 winning Brown bet would have produced a profit of £19 – today such a wager offers £27.

But the big question that those betting against the Chancellor have to ask is – if not Gordon then who? We have seen one potential challenger after another fall by the wayside and it is hard to make a case for anybody within the cabinet. What about looking wider afield?

Four years ago three senior ministers resigned over Iraq: one, Robin Cook is sadly no longer with us; the second Claire Short is no longer with the Labour party; while the third, John Denham, remains as a Labour MP and has been a regular critic of the Blair administration as chair of the Home Affairs committee.

Given the way that Iraq and its aftermath continue to overshadow Labour could Denham – who had the courage of his convictions in 2003 – be the man who could mount a plausible challenge?

For as well as his stand on Iraq Denham is one of the dwindling band of Labour MPs to represent a seat in southern England – Southampton Itchen which he took off the Tories at the 1992 general election.

One person who has been talking up Denham’s strengths is the influential Labour blogger, Paul Linford. Last week he noted “Denham is a sensible leftie who in most respects holds perfectly mainstream Labour Party views, notably on the importance of tackling inequality. He also, of course, has relevant recent high-level ministerial experience as a minister in the Home Office. John Denham is a man of high principle who in my opinion would make an admirable Prime Minister.”

This BBC interview from last September shows what an effective communicator he is. I think he is quite impressive with an approach that is very much in tune with the moment.

What strikes me is that a contender who had resigned his post over Iraq is in a completely different category from almost anybody else. If the party wants to draw a line under that unhappy episode then choosing someone who took such a stand is the way to do it.

A Denham victory would leave David Cameron as the only one of the three main party leaders to have voted for the war and help Labour counter the Lib Dem’s USP on the issue.

The more I have thought about it the more logical a Denham bid appears and over the weekend I did put £6 on Denham at average odds of more than 320/1.There’s been no hint from Denham that he is even interested and I am still maintaining my betting position on Gordon. But things can happen.

Mike Smithson