A Powerful Majority

Matthew Holehouse writes:

We have a new toy on Telegraph Politics: our Vote 2015 results forecaster. We have teamed up with Electoral Calculus, the brilliant analysis site run by Martin Baxter, to produce a daily snapshot of how Parliament will look on the morning of May 8, 2015. It works by taking the results of the latest polling – we use YouGov’s daily tracker poll – and applying the swing against the results of the last election to see which seats are likely to fall.

In May 2010, the Tories won 36.9 per cent of the vote, Labour 29.7 per cent, the Liberal Democrats 23.5 per cent, and Ukip 3 per cent. It left the Tories 19 seats short of a majority. Today’s tracker has Labour on 40 per cent, the Tories on 30, the Lib Dems on 10 and Ukip on 14. Our model suggests that if we went to the polls today, Ed Miliband would gain 120 seats and become prime minister with a powerful majority of 106. (By comparison, Blair had a majority of 167 in 2001, cut to 67 in 2005.)

The Tories would lose 98 seats, down to 223, and the Lib Dems would lose more than half, down from 57 to 23. Among the victims of the 10-point Labour surge, according to the forecast, would be Danny Alexander, the Chief Secretary to the Treasury (Inverness, Nairn, Badenoch and Strathspey, majority 8,765); Chloe Smith, the Cabinet Office minister (Norwich North, majority 3,901); and Anna Soubry, the Health Minister (Broxtowe, majority 389).

Other losers would include Jeremy Browne, the Home Office minister; Simon Hughes, the Lib Dem deputy leader; Edward Timpson, the Children’s minister; and Robert Halfon, the Harlow MP who has successfully campaigned for lower fuel duty. And all of the Tories’ gains would come from the Liberal Democrats.

All the same, some health warnings: it is merely as a snapshot of what the polls show today, not in two years' time. The Tories hope a growing economy and scrutiny on Miliband will narrow the gap rapidly. And it is based on a universal national swing, with parties losing votes by the same amount in each seat. That makes predicting individual results more tricky.

In reality, some hardworking MPs will hang on to wafer-thin majorities, while some – due to personal failings or a tough opposition – will lose what could have been holdable seats. But at a national level, these local factors balance out, as Martin's correct forecast of the 2010 results testifies.

Predicting Scotland and Wales is tricky, due to a lack of regular local polling. (YouGov polls Ukip separately but treats Nationalist and other minority parties as "other".) Then there is Ukip. Nigel Farage’s party polled around 23 per cent of the vote in May elections.

YouGov puts its support on 14 per cent. But under our forecast – which accounts for its share of the vote changing at the expense of other parties equally – it would fail to win a single seat. Under Martin’s modelling, if support was evenly concentrated Ukip would not start to win seats until their national support goes above 23 per cent, winning five seats at 24 per cent and 79 at 28 per cent.

Two caveats though. What the model does not show is if Ukip’s support is coming disproportionately from one party – such as the Tories – which could change a significant number of races, potentially to Labour’s advantage. And the party leadership is confident there are constituencies where support is concentrated enough to win, regardless of the national share of the vote. We shall see.