Theresa May’s government thrown into turmoil as Brexit secretary David Davis and deputy Steve Baker resign

Prime Minister Theresa May took a major hit late last night after Brexit secretary David Davis resigned from his post, effective immediately.

Davis exchanged letters with Number 10 after his position became untenable following the Cabinet away-day on Friday when May’s top team finally thrashed out a position of the UK’s future trading relationship with the EU.

Davis signed up to the plan agreed by the Cabinet in closed talks at Chequers on Friday.

However, in his resignation letter to the Prime Minister last night Davis wrote: "In my view the inevitable consequence of the proposed policies will be to make the supposed control by Parliament illusory rather than real. As I said at Cabinet, the “common rule book” policy hands control of large swathes of our economy to the EU and is certainly not returning control of our laws in any real sense".

The Prime Minister replied in her letter: "I am sorry that the Government will not have the benefit of your continued expertise and counsel as we secure this deal and complete the process of leaving the EU".

However May also said she did not agree with Davis's "characterisation of the policy we agreed at Cabinet on Friday. Parliament will decide whether or not to back the deal the Government negotiates, but that deal will undoubtedly mean the returning of powers from Brussels to the United Kingdom."

One of Davis's deputies in the Department for Exiting the EU (DexEU), Steve Baker, is also reported to have resigned. Davis is said to have had a "you go, we go" pact with Baker and Suella Braverman, another DexEU minister.

Prominent ministers who were part of Vote Leave during the EU referendum campaign including environment secretary Michael Gove and foreign secretary Boris Johnson assented to the plan, although Johnson reportedly described the latest proposals as “polishing a turd”.

May now also faces a crunch meeting this evening as she attempts to keep her party onside amid rumblings of a leadership challenge and a growing backlash over her newly revealed Brexit negotiating position.

She is due to meet Conservative backbenchers on the party’s powerful 1922 Committee to try to persuade them to back the plan, which would involve a customs union for goods alongside regulatory divergence for services.

May's proposal is to create a free trade area between the UK and EU "which establishes a common rule book for industrial goods and agricultural products".

The government will unveil a white paper on Thursday, giving more details on the model.

Davis was made Brexit secretary in 2016 and was responsible for negotiating the UK withdrawal from the EU.