I wrote yesterday of how Labour will need a 19.7% swing to defeat Nick Clegg at the election, while the SNP will need a 20.8% swing to unseat Douglas Alexander.
The size of these swings relative to those typically seen at general elections is enormous – but they are not uncommon.
At the last election, three constituencies saw swings of over 15%. One even topped the 20% mark:
The result in Redcar was a gain for the Liberal Democrats from Labour. It was a remarkable turnaround in a constituency that once boasted former Northern Ireland secretary Mo Mowlam as its MP. Ian Swales was the victor in 2010, but he is standing down this year and I fully expect Labour to retake the seat.
None of the other seats in this top five changed hands at the 2010 election. Ashfield, Merthyr Tydfil & Rhymney and Barnsley East remained Labour seats, despite the Lib Dems coming within 192 votes of taking Ashfield. All three ought to be held by Labour this year.
The Tories had won Hemel Hempstead from Labour in 2005, and at the 2010 election Mike Penning turned his majority of 499 into 13,406. He’ll be safe this year.
It’ll be fascinating to see if we get any swings on 7 May that beat Redcar. I wouldn’t be at all surprised if the record was set in Scotland.