Philip Hammond, the chancellor, is among the ministers plotting to force the prime minister to change tack

The prime minister is facing a fresh cabinet mutiny after “remain” ministers began secret talks behind her back to force her to adopt a new plan B for Brexit.

Senior ministers are also in private discussions with the Democratic Unionist Party (DUP) to draw up an alternative Brexit blueprint in the event that her deal is voted down by parliament.

The revelations come as Theresa May today launches a two-week PR blitz to save her government from collapse with an open letter to the nation proclaiming the deal — due to be signed today in Brussels — as “a new chapter in our national life”.

Chief EU negotiator Michel Barnier greets May in Brussels yesterday PHILIPPE LOPEZ

She writes: “I want that to be a moment of renewal and reconciliation for our whole country. It must mark…