While Labour gained 77 seats and the Conservatives lost 33 in last week’s English local elections, a projection on what would happen at a general election based on the results suggested both parties would be roughly neck and neck; each gaining 35 per cent of the vote in another hung parliament.
This, argued Sir John, meant that for Jeremy Corbyn to get into Downing Street, his party’s results in Scotland would be crucial.
Noting how Labour would not need many votes to take a swath of seats north of the border, the psephologist pointed out how among the 64 target seats Labour would need to form a majority, some 18 were in Scotland, where there was a disproportionately high number of marginal constituencies.
Sir John told Sunday Politics Scotland: “The truth is if the SNP vote were to go up a couple of points at the next election, Labour’s chances of getting an overall majority are significantly diminished. If the SNP vote just falls a couple of points and the Labour Party are doing roughly where they were last time, then Labour’s chances improve significantly.
“So, Scotland is now absolutely central to the battle for power at Westminster, particularly as far as the Labour Party is concerned,” declared Sir John.
Last year, Mr Corbyn insisted that Scotland “holds the keys” to him getting into power; at last year’s election, to the surprise of some, it gained six seats and came close in a number of others.
On the basis of Sir John’s assessment of the state of the parties and the local election results in England, Labour’s performance in Scotland now, therefore, seems even more key in determining whether or not Mr Corbyn can get into Downing Street.