Is this the woman who could help determine the date?

This is Deborah Mattinson, joint chief executive of Opinion Leader Research, a pollster for the Labour party for the past two two decades and someone who is likely to play a key role in advising Brown on whether to go for an early general election.

In recent months she has been a big critic of one or two surveys that have not been favourable to the Chancellor.

Brown will need good advice because one of the biggest gambles he’ll have to make when he takes over will be a decision whether to “cash in” the expected succession poll bounce by calling an immediate General Election.

There are huge dangers with an early election. If he gets the election timing wrong he’ll go the way of Labour’s last leader to take over while in government, Jim Callaghan, who had barely three years in the top job.

But Brown is a historian of the movement and is acutely aware of Callaghan’s decision in October 1978 not to go the the country then. By waiting until the following year Callaghan had to watch as Labour’s ratings fell during the “winter of discontent” and by the spring there was a totally different environment.

Many argue that it was Callaghan’s caution that autumn that paved the way for Thatcherism.

If Gordon decides to go for it and succeeds he will have his own mandate be able to cut himself off from what the Tories are now calling the “Blair-Brown” years.

So what sort of polling evidence would Mattinson and other advisers be looking for? At what level would it be worth taking the risk and recommending that Gordon should go to the country immediately?

Given the electoral arithmetic that is likely, once again, to favour Labour then the current polls don’t have to move all that much for a gamble to be worth-while. Even with the boundary changes Brown could get a working majority if Labour just equalled the Tories on votes. The party should still come in top place with GB vote deficits of less than 5%.

The main seat calculators, the ones from Martin Baxter and Anthony Wells, suggest that David Cameron would need a 10% lead on votes to be sure of forming a majority government.

All of this would reduce the down-side risk for Gordon and his team which could expect a media honeymoon in those first few weeks after the hand-over. In the post-Blair world everything will look different.

There is also the element that Government’s tend to recover in the ratings during a campaign – though whether that applies to the same extent with modern polling methodologies is harder to predict.

My guess is that if the three polls that form part of the PBC Pollling Average – ICM, YouGov and Populus – are all showing Labour and the Tories to be neck and neck then it would be worth the gamble but I think that Gordon would be looking for 2-3% margins.

Mike Smithson