Sir Simon Stevens, left, the chief executive of NHS England, with the health secretary Matt Hancock. The government complain that they do not have enough power over Sir Simon

Boris Johnson has been accused of starting a “turf war” with NHS bosses as it was revealed he will use a new law to exert more control over the health service.

Dominic Cummings, the prime minister’s chief aide, believes that at present the law gives Sir Simon Stevens, the head of NHS England, excessive freedom, making it hard for Downing Street to impose its will.

Legislation to be introduced this year will include powers for ministers to give orders to Sir Simon, who is meant to be operationally independent.

However, the move has sparked a furious backlash with Jonathan Ashworth, the shadow health secretary, accusing the prime minister of embarking on a new top-down reorganisation.

Mr Ashworth said: “Boris Johnson has promised he will get