First of all I must congratulate Chloe Smith everyone involved in the Norwich North by-election on their victory. It is no mean achievement to see a 16.5% swing, which would be more than enough, if repeated across the country to see a Conservative government.
The numbers geek in me wondered what this would mean for Wandsworth.
This needs prefacing with lots of caveats. Swing is a very imperfect measure. It is never uniform and local issues and campaigns mean it’s dangerous to draw conclusions from it. The method I’m using (the Butler Swing) only takes account of the top two parties, so it also ignores the impact of a strong campaign from minor parties. However, since Norwich North and all the Wandsworth seats are fairly straightforward Labour/Conservative fights, it’s not entirely unreasonable to put the numbers in and see what happens.
The Butler Swing basically takes the average of the change in vote share for the top two parties. So in Norwich North the Conservative vote share increased by 6.29% and the Labour vote share dropped by 26.70% – an average swing of 16.49% from Labour to Conservative.
In Wandsworth this would mean, very simply, all three seats would be Conservative – a 16.49% swing from the 2005 result would see:
- In Battersea Martin Linton’s 163 majority would easily be overturned, becoming a 13,374 vote majority for Jane Ellison.
- In Putney Justine Greening would see her 1,766 majority increase to a 13,828 majority over Labour’s Stuart King.
- Even in the ‘safe’ Labour seat of Tooting, Sadiq Khan would see his 5,381 majority turn into a Conservative majority of 8,328 for Mark Clarke.
Even at half the swing, 8.25% from Labour to the Conservatives, all three seats would return Conservatives (majorities of 6,610, 7,801 and 1,477 in Battersea, Putney and Tooting respectively).
I’ve compared the current situation to 1997, which I saw from the losing side. Twelve years later the Norwich North result is almost a mirror image of the Wirral South by-election in 1997, which saw a 17% swing from the Conservatives to Labour and preceded the landslide Labour victory in the general election when they got a national swing of over 10%.
There’s no doubt that the Labour candidates in all three seats will be looking at the results and making the same comparisons. There’s going to be some fierce campaigning over the next year.