The new Prime Minister Rishi Sunak has given the Tories an electoral bounce: an increase of 10 MPs from the 48 MPs that Electoral Calculus estimated Liz Truss would have won in the dying days of her brief period in office. The size of the bounce is consistent with academic research that it is the performance of parties not the personality of leaders that wins votes or, in the case of Liz Truss's performance, loses votes.
The bounce, a one percent uplift in the polls, is high enough to regain the title of Her Majesty's Loyal Opposition from the Scottish National Party. However, the loss of 307 seats on a massive swing of 19 percent to Labour would leave the Conservatives the weakest Opposition Party since the Labour Party's massive defeat in 1931.
Since becoming party leader Sir Keir Starmer hasn't changed his personality but he has changed the image of the Labour Party from that of an advocate of extreme policies to a party that could be trusted with control of government. A hypothetical election held today would likely give Labour 498 seats, a far bigger majority than won by Tony Blair in 1997 or Boris Johnson in 2019. Moreover, the landslide would not depend just on the fall in Conservative support. For every 10 supporters the Conservatives have lost, Labour has gained 9 new supporters.
The size of Labour's predicted majority means that there is only a one percent probability that Labour would become the largest parliamentary party but short of an absolute majority, thereby depending on third parties to win a vote of confidence. A Conservative collapse would likely deliver only half a dozen seats to the Liberal Democrats and less than that to the Scottish nationalists.
A landslide Labour victory would shift the evaluation of the party's competence from comparison with a government in disarray to the tougher test of whether it appears to be a party capable of having a firm grip on government. Almost two-thirds of MPs forming a big Labour majority would be first-term MPs, needing to learn the ways of the House of Commons and the Parliamentary Labour Party. Even if new MPs had served as a spin doctor to an MP in opposition, this would not provide the understanding that comes with being a government minister.
With more than 100 government offices to fill, Starmer would have to give government appointments to more than half of today's Parliamentary Labour Party of 196 MPs. The key question would no longer be whether an MP is a Corbynite or a Blairite but whether he or she is up to the challenge of holding office or likely to be a political embarrassment. In recognition of this, Starmer has arranged for Labour MPs to get tutorials on how to be a minister but this is a weak alternative to learning from the experience of being in office.
For Rishi Sunak stabilizing the financial markets is not a sufficient condition for political success. He must also transform a disastrous electoral legacy left him by Boris Johnson's Partygate and Trussonomics. He has just over two years to get the Conservatives out of the depth of a hole deeper than any the party has occupied in living memory.
Richard Rose is Britain's senior psephologist and an expert on party government. His new book 'How Sick is British Democracy?: a Clinical Analysis' is published by Palgrave.