Could we be heading for the biggest electoral upset in modern political history?

It's only been a few hours since polls closed and it already looks all but over for Labour's chances of forming the next government.

Nuneaton is the first big Labour target which needed just over a 2% swing for Labour to gain it. Instead there was actually a 3% swing to the Tories.

Even in London, where Labour had their best hopes of making gains, the results look poor.

Both Battersea and Putney have seen swings to the Tories and in Labour's London campaign chief Sadiq Khan's Tooting seat, he managed just a 0.2% swing.

And that's with the Lib Dem vote collapsing in the seat. Other Labour targets including Croydon Central aren't looking good according to those on the ground and the Tories now even fancy their chances of gaining Hampstead and Kilburn from Labour.

Labour sources tell me an imminent leadership contest is now almost certain.

It's still very early days, but the results we've seen so far suggest that the Conservatives have actually done significantly better than the earlier dramatic opinion poll suggests.

In fact almost unbelievably it's increasingly looking like David Cameron could be heading back into Downing Street with an overall majority. Britain's leading psephologist John Curtice has already indicated this is now a very strong possibility.

It would be a remarkable turnaround and a truly historic victory. The results we've seen so far suggest he just might pull it off.