Don't get carried away with the shortening of the Labour lead over the Conservatives in the polls. It should have been expected anyway. Last week was wall to wall coverage of the Labour conference so that was likely to increase the poll ratings for Labour. This week it has been wall to wall coverage for the Tories. So Labour's artificial high has been deflated and the Tories have taken up some of the slack instead. Polls over the weekend will be more interesting but still contaminated by conference coverage.
Those polls however will not be the ones Brown will be studying this weekend. Instead it will be the evidence from the marginal constituencies. After all, they are where elections are won or lost. He will also need to look at their canvass data as well.
Do not expect him to stop the countdown to the launch of the election. He has partly painted himself into a corner and to call off the election now would make him appear weak and Cameron strong. That could have lasting effect.
In addition, in looking at the data from the constituencies, Brown will also be aware of what will happen if he does not go now. More Tory millions will be poured into the marginals, firming up the Tory vote over the winter and spring. The constituency arms race is not one the Labour Party can sustain for too long and with a weakened activist base from a decade in power, getting those who are left out to campaign now will be easier than raising their expectation, dashing them and then trying again in the spring.
Throw into the melting pot as well the slowdown in the economy. Growth will be lower than it was been over the past decade and that will put a brake on public spending. That means bad new stories on services. It could mean some tax rises as well, especially on council tax. And a big increase in council tax next April, a month before a spring general election would be bad news for Labour.
Brown was arguably foolish to let expectation of a snap autumn election build up so much momentum. It is likely he reckoned on a more comfortable general opinion poll lead and positive headlines in the run up to calling the election. It is characteristic of the arrogance of Labour that they could assume such comfort.
So Labour are now in a position in which their expectation is now that they get back simply with a majority, rather than an improved one. Brown let the election expectation rip because he thought he could get an increased majority. After all, going to the country well before you need to just to come back with a more difficult Parliamentary position is the suicidal form of government that doesn't strike me as being the sort of aim Brown would harbour.