Political realities constrain Sunak over when to call an election

A later election would give PM more time to turn the economy around but a spring surprise is not out of the question

One of the few political powers to rest almost entirely in the prime minister’s hands is the decision over when to call an election.

Rishi Sunak invoked that power on Thursday to put himself back on the front foot after several weeks dominated by speculation – often fuelled by senior Labour MPs – that there could be a vote as soon as May.