Barring miracles or disasters on the campaign trail, a change of government appears to be just weeks away

Here we go again. For the third time in a row, the general election starting gun has been fired early by a Conservative prime minister. Theresa May started well ahead and nearly lost it all. Boris Johnson started well ahead and took that lead to the bank. Rishi Sunak doesn’t start with his predecessors’ advantages – his is the gamble of a man with nothing to lose.

Victory requires an unprecedented turnaround. All the evidence suggests it is instead Sunak’s Labour opponent, Keir Starmer, who is about to make history. But he, too, faces a mammoth task in the coming weeks as he seeks to take Labour from its worst Commons defeat in 90 years to a governing majority in one big leap.