The UK must not agree to extend the Brexit transition period unless the EU ditches its demand for a backstop, the Brexit Secretary suggests today.

Writing in The Telegraph, Dominic Raab said an option floated by Theresa May of the UK remaining tied to the EU beyond December 2020 would only be an “alternative” to the insurance plan insisted on by Brussels.

His intervention will be welcomed by pro-Brexit MPs, who reacted with fury to the Prime Minister’s suggestion that the Government could offer to extend the transition period “by a few months” as well as agreeing to a backstop.

Brussels has insisted a fallback mechanism is necessary to protect Northern Ireland from a hard border if negotiations for the future relationship with the EU break down. The suggestion it could be ditched entirely is likely to infuriate EU negotiators.

It comes as Mrs May faces growing pressure from MPs and the Cabinet over apparent concessions discussed between British and EU negotiators.