The counting is ongoing in Eastleigh, with the Lib Dems increasingly confident that they've held the seat. The party, which first won the constituency in 1994 (another by-election), expects its majority to be in the thousands, not the hundreds (it is currently 3,864).
Both the Lib Dems and Labour are predicting that UKIP has finished second, pushing the Tories ino third place. If true, this would be a disastrous result for David Cameron. His old rival David Davis was likely right when he suggested  earlier this week that it would provoke a "crisis". But Cameron's right-wing critics will have trouble explaining why the Tories performed so poorly after a hard-edged campaign that focused on immigration and welfare and after the promise of an in/out EU referendum.
Labour is resigned to finishing fourth, although the party believes it has increased its share of the vote from the 9.6 per cent recorded in 2010. The result will undermine Ed Miliband's "one nation" narrative but shadow ministers point out that while the seat is 16th on the Tories' target list, it is 258th on Labour's. The swing required to win Eastleigh would put Labour on course for a majority of 362.
Turnout was a relatively impressive 52.8 per cent, down from 69.3 per cent at the general election. We'll bring you the result as soon as it's announced around 4am.