Following on from yesterday’s post on whether or not the presence of UKIP had cost the Conservative party a number of seats…
cim has done some analysis suggesting that a UKIP candidate produces a net increase in turnout of about 2.5% – 1,000 votes. However, the average UKIP candidate took around 1,600 votes, suggesting that they’re only taking around 40% of their votes from other candidates and the remainder from potential abstainees. If about half of that 40% would have voted Conservative, and the remainder voted for another minor party if one was present, then we can find the seats where the Conservative candidate was less than 20% of the UKIP vote away from beating their opponent.
There’s six of them – albeit one by a mere four votes, so we can perhaps call Dudley North a 50-50 chance.
If we raise the defection rate to 30%, we still have the same six seats under the threshold; if it’s raised to 40% – indicating that all defectors to UKIP came from the Conservatives – they would recover a seventh seat, Great Grimsby, from Labour.
Six seats is not enough to produce a definite majority, of course – but it’s certainly a non-trivial number, especially since they would come directly from the opposition. Had they taken these six seats, we’d be looking at 311 for the Conservatives versus 301 for an opposing Lib Dem-Labour coalition; it would become substantially harder for a reasonably robust coalition to form against the Conservatives, and so they would have a better chance at gambling on a minority government.
Historically speaking, it’s a plausible number. The Referendum Party (remember them?) in 1997 took 2.6% of the votes, and are estimated to have cost the Tories about four seats. UKIP took 3.1% of the vote this time around, so six seats is well within the bounds of plausibility.