Could polling day bring a surprise surge?

Can Gordon Brown get the sort of late surge he needs? What are the precedents? Folk sometimes talk about a late surge in 1992 that saved John Major but the text books tell us that was actually more of a case of the polls misreading things throughout the election.

February 1970 does seem to have seen a late surge of something over 2 per cent, Labour to Conservative. Specific events – England falling out of the world cup and some bad trade figures – are thought to have been the cause.

Any equivalents today? Some slightly encouraging economic data and the alarming scenes from Greece. For people still undecided could those images from Athens make their pencils suddenly switch back to Labour?

Probably not in enough numbers to stop David Cameron topping the poll. How about the great undecideds. Are they really in greater numbers than ever? We do seem to hear that quite often in recent elections.

One recent poll suggested 12 per cent are currently undecided. This close to an election the text books would tell us normally that about half of them are not going to vote and the other half will vote more or less in line with the current alignment of the polls.

But maybe these aren’t normal times.

Another key question – how do nervous Lib Dem supporters break if, at the last minute, they pull back from supporting Nick Clegg and go for one of the other two?

Again, a recent poll suggests that Lib Dems are still breaking 60:40 in Labour’s favour over the Conservatives when asked where would your vote go if you were choosing between the other two.