How Many Seats Did UKIP Cost The Conservatives In 2010?

As you may recall, the result of the May 2010 general election was:

• Conservatives - 306 (including 1 Deputy Speaker)
• Labour - 258 (including 2 Deputy Speakers)
• Liberal Democrat - 57
• Northern Ireland parties - 18
• Scottish National Party - 6
• Plaid Cymru - 3
• Greens - 1
• The Speaker - 1

One thing that is sometimes argued is that the Conservatives lost loads of seats due to the intervention of the UK Independence Party, with the argument that if only the Conservatives had been more Eurosceptic, UKIP wouldn't have been there, and we just need to add together the Conservative and UKIP vote to find out how many votes a more Eurosceptic Conservative party would have had. And therefore, we are supposed to find that as a result of Prime Minister David Cameron not being Eurosceptic enough, there were sufficient seats won by Labour and the Liberal Democrats to prevent a Conservative majority Government.

Sounds simple and obvious enough, but how accurate is it?

In May 2011, the people rejected a move to the Alternative Vote. Meanwhile, a paper was published looking at AV's consequences. Some of the valuable data in there is looking at what the second preferences of UKIP voters were - and so we can use these to model how UKIP voters would have voted if there had been no UKIP candidates. And doing this constituency-by-constituency we can model the 2010 election without UKIP.

And we find only 6 seats where UKIP's absence would have changed the winner:

Constituency	MP	Winner without UKIP's presence
Bolton West	Julie Hilling (Lab)	Susan Williams (C)
Dorset Mid & Poole North	Annette Brooke* (LD)	Nick King (C)
Dudley North	Ian Austin* (Lab)	Graeme Brown (C)
Hampstead & Kilburn	Glenda Jackson* (Lab)	Chris Philp (C)
Solihull	Lorely Burt* (LD)	Maggie Throup (C)
Southampton Itchen	John Denham* (Lab)	Royston Smith (C)

An asterisk indicates someone who was an MP prior to the election. Williams was in the list of working peerages announced in August 2013.

One interesting thing to note is that UKIP voters prefer the more pro-European Union Liberal Democrats to Labour, and UKIP's absence would have given the Liberal Democrats very narrow misses in both Oldham East & Saddleworth and Sheffield Central.

6 seats can make a huge difference. In both the October 1964 and October 1974 general elections, 6 more Conservative MPs would have led to a hung Parliament with Labour as the largest party rather than a Labour majority Government. At the February 1974 general election, 6 more Conservative MPs would still have meant a hung Parliament, but one where the Conservatives - rather than Labour - were the largest party.

Without UKIP, the overall result would have been:

• Conservatives - 312 (including 1 Deputy Speaker)
• Labour - 254 (including 2 Deputy Speakers)
• Liberal Democrat - 55
• Northern Ireland parties - 18
• Scottish National Party - 6
• Plaid Cymru - 3
• Greens - 1
• The Speaker - 1