What is really going on in politics? Get our daily email briefing straight to your inbox Sign up Thank you for subscribing We have more newsletters Show me See our privacy notice Invalid Email

Theresa May was dealt a crushing new Brexit blow today as one of her own Cabinet colleagues warned she could face defeat.

Commons Leader and arch Brexiteer Andrea Leadsom said Britain must be able to quit a customs backstop without the EU's permission.

But underlining the confusion at the heart of Government, Education Secretary Damian Hinds warned such an outcome would be "very, very unlikely".

It comes as No 10 is braced for more ministerial resignations after Boris Johnson's brother Jo quit as Transport Minister last week and demanded a second referendum.

In 48 hours the Prime Minister is due to brief her Cabinet on her latest plans for Brexit.

She wants a deal with Brussels in the next few weeks which she could then take to MPs for a vote in the UK Parliament before Christmas.

(Image: REUTERS)

But MPs of all persuasions are today warning she could lose the vote - triggering chaos and a potential no confidence challenge.

Brexiteers are trying to stop her implementing a 'backstop' (backup plan) that would extend EU customs rules across the UK, with no guaranteed way of getting out.

As Leader of the Commons, Ms Leadsom is not technically a Cabinet minister. But she attends Cabinet, and stood against Mrs May for Tory leader in 2016.

She told BBC Radio 5 Live: "I am working towards getting a deal that does not require the UK to be stuck, trapped in a customs arrangement.

"I’m sticking in government to make sure that’s where we get to in the end.

"I don’t think that something that traps the UK against our will would be sellable to members of Parliament."

Yet it came just minutes after another Cabinet minister, Damian Hinds, warned it was "very very unlikely" Brussels would let the UK quit a backstop.

(Image: Getty Images)

"If you have too hard a line about saying, 'well we must just have a totally unilateral exit, or there's an absolutely fixed, hard end date', that is... very, very unlikely that is going to be negotiable with the other side," Mr Hinds told the BBC.

The row is over plans for a "backstop" - backup plan - to keep the UK covered by EU customs rules if there is no deal.

It is designed to ensure border checks don't start between Northern Ireland, in the UK, and the Republic of Ireland, which is in the EU.

But critics fear it will drive a wedge between rules for Northern Ireland and the rest of the UK.

And they believe it will keep the UK tied to the EU with no clear way of getting out.

Also today:

Tory Brexiteers and the DUP united, warning explicitly they will vote down the deal if there is no compromise over the backstop.

warning explicitly they will vote down the deal if there is no compromise over the backstop. Labour warned it will "stick to its guns" and vote down Mrs May's "political hoax" deal as it stands.

and vote down Mrs May's "political hoax" deal as it stands. Tory Justine Greening vowed to defeat the deal - showing a fightback by Remainers in the party.

- showing a fightback by Remainers in the party. The head of the Armed Forces declared "we stand ready to help" in a No Deal.

in a No Deal. Three more Tory ministers threatened to quit, following Jo Johnson who resigned warning of the greatest crisis since Suez.

(Image: PA)

UK negotiators hoped Brussels would agree an independent arbitration tribunal which would stop the Irish backstop being used to trap the UK in an indefinite customs union.

A Whitehall source described it as "the Government's life-support machine".

But in a separate development, the EU appears to have dashed the hopes.

A source told the Sunday Times: "By rejecting the proposal, the EU has just turned the oxygen off.”