Boris Johnson is set on reforming the civil service – but this is the warning he needs to listen to before he does

If the prime minister and his cabinet continue to shoot the messenger, they will end up wounding themselves in both feet, says Andrew Grice

While the emerging shake-up looks like centralisation, the prime minister's aides insist it is about having a small, efficient centre based on Number 10, the Cabinet Office and Treasury (Getty)

Persistent grumbling about Boris Johnson among Conservative MPs has turned to anger during the fiasco over exam grades, and despair about the aura of incompetence hanging over his government.

His usual approach to party management is an occasional speech to rally his backbench troops. But in recognition that he has a problem, he will meet more Tory MPs in small groups after the Commons returns from its summer break on 1 September.

Johnson and Gavin Williamson, the beleaguered education secretary, were lucky the Commons was in recess while the exam controversy erupted. By the time MPs get their teeth into what went wrong, the storm will probably have abated. But there is one Tory critic the prime minister should listen to: his fellow Brexiteer Bernard Jenkin, who chairs the Liaison Committee of senior MPs and previously chaired a select committee monitoring Whitehall.