The North is an electoral desert for the Conservatives. There is the occasional oasis of support but even these are becoming rarer by the day. Though the North has never had a majority of seats for the Conservatives in recent history, they need votes and seats here to be able to mount a credible challenge and win a general election. The hard reality is that Cameron has to win in the North as well as the South and if he doesn't, he ain't going anywhere.
So in Sedgefield, where his candidate starts in second place, he should be looking to retain the runner up position and increase his vote. He has to show that he can appeal to Northern voters in places like Sedgefield. The constituency itself contains many towns, villages and rural areas that an observer would think were natural Conservative territory. Yet Cameron's appeal in these places is at best barely registering on the political radar.
Slipping into 3rd place in Sedgefield would be a disaster for Cameron. It will show clearly that they are losing badly in the North, whatever is happening in the South. A poor performance for Cameron's Conservatives cannot just be dismissed. It would be unreasonable to suggest the Conservatives' only measure of success would be to win Sedgefield. This is after all a seat that has been solidly Labour for three generations. But serious questions about the ability of the Conservatives to win a general election should and must be asked if Cameron fails to make inroads into Labour's vote here in the North.