According to the Electoral Reform Society, this link gives an analysis of all constituencies based on how 'safe' or 'marginal' they are. ( https://spreadsheets.google.com/ccc?key=0AgdO92JOXxAOdHRGZmRTOWItcnFDTFpHMzRPRmF6RFE&hl=en )
From this, they state that regardless of swing or any other factor, the parties will effectively start with the following number of results 'in the bag' :
Britain's 'Safe' Parliament
Party Safe Seats %
Con 172 45.03%
Lab 165 43.19%
LD 29 7.59%
PC 2 0.52%
SNP 3 0.79%
NI others 11 2.88%
That is 382 of the 646 seats in Parliament where the donkey with the coloured ribbon will be returned.
The seats that matter are the marginals and they are classified as
Category Number
Marginal1 – a Labour seat that was marginal in 2005 but probably won’t be in 2010 because it is highly vulnerable and will probably fall easily 43
Marginal2 – the real front line between Labour and Conservative government 78
Marginal3 – a seat Labour could lose if the election goes badly, but at the moment is probably likely to remain Labour 45
LD long shot – Often Lib Dem seat gains are not closely related to the apparent vulnerability on the numbers from last time. These seats are ones where a ‘left field’ gain cannot be ruled out, or seats where despite a fairly small majority over Lib Dem their chances of winning are not enough to qualify it as a true marginal 15
Marginal – a marginal seat held by a party other than Labour, including Con/LD seats, a few Con/Lab seats, SNP seats, LD seats, NI etc 75
3WAY – a three way marginal (these are rare) 12
Therefore, this election is all about the Marginal2 & Marginal3 seats. Out of interest, both So'ton seats are Labour Marginal3.