Picture exclusive: Boris Johnson leaves his temporary office in Admiralty House, central London, at 3.02pm on Wednesday on his way to see the Queen and be made prime minister

Boris Johnson has set up a “war cabinet” to deliver Brexit “by any means necessary” by October 31 as a senior cabinet minister warned that there was “now a very real prospect” of no deal.

In a dramatic shift Michael Gove, the minister responsible for no-deal preparations, said the government was “working on the assumption” that Brussels would not strike a fresh agreement. This morning Rishi Sunak, the new chief secretary to the Treasury, said ministers were “turbo-charging” no-deal preparations.

In a Whitehall revolution, Johnson will make every decision on Brexit policy with a team of just six senior ministers — all of them Brexiteers who support no deal.

Starting tomorrow, the war cabinet — Gove; the chancellor, Sajid Javid; the foreign secretary, Dominic Raab;