Kellner’s Law rewritten

Just as I thought I had got the Four Square Rule firmly imprinted on my brain – that the Conservatives need to be four points ahead in share of the vote to be the largest party at the election next year – Peter Kellner returns from another trip up the mountain with a new tablet.

He has posted an analysis on the YouGov website that suggests the collapse of Liberal Democrat support could remove most of Labour’s advantage under the electoral system. Having previously assumed that the Lib Dems would recover to about 14 per cent next year, he has now re-run the calculations assuming that they stay stuck on 8 per cent, which is their current average in the opinion polls.

What he has also done, though, is calculate two additional factors. One is the incumbency effect, the personal following enjoyed by Lib Dem MPs. The other is what he calls the “sophomore” effect, the boost likely to be received by Tory MPs first elected in 2010, an advantage enjoyed by new MPs in previous elections.

On these assumptions – Lib Dem national vote share of 8 per cent, Lib Dem incumbency advantage and Tory sophomore effect – the “bias” in the voting system disappears. If Labour and the Tories have an equal shares of the vote, says Kellner, it would be “too close to call” which party would emerge with the most seats in the Commons.

If Dominic Cummings, former special adviser to Michael Gove (pay wall), is right about Nick Clegg – “He’s a goner; people look at him and just have contempt for him, he’s the author of his own misfortune” – Labour supporters should contain their satisfaction.