If the early results are anything to go by Labour are facing a far worse defeat than predicted. They were defending 493 seats and predicted to lose 200. Losing half their seats was seen as being the extreme end of how bad it could get for them. So far it looks like being a much, much bigger defeat than that.
The pundits are so far more interested in cabinet resignations but I suspect when the scale of these results sinks in they could be of more importance than the departure of James Purnell in terms of the pressure on Gordon Brown to go.