I am not sure whether it’s me or ministers who are the more naive.

Because last night I was persuaded by Cabinet sources a breakthrough was nigh in talks to resolve the Brexit deadlock between the Government and Labour.

But the talks are already on the verge of collapse - with each side making charges it is the other side which is negotiating in poor faith.

Labour sources say the memorandum sent by the PM to Jeremy Corbyn this afternoon shows Theresa May has not shown the flexibility her colleagues expected.

Theresa May has been working with Labour to find a way forward. Credit: PA

What has disappointed Corbyn and his Shadow Brexit Minister Keir Starmer is - they believe - the government is ruling out asking the EU to rework the Political Declaration on the UK’s future relationship with the EU.

What the PM has proposed is a so-called wrap-around statement, that would toughen up proposed protections of workers’ rights, and would give a greater role for parliament as and when the future relationship is being negotiated, including a prior “entrenchment” process to embody whatever kind of future relationship MPs favour within the forthcoming Withdrawal and Implementation Bill.

There is in the memorandum a nod to MPs having a vote to decide whether there should be a confirmatory referendum. But apparently it is desperately non-committal.

Corbyn celebrates the result of a by-election in Newport, south Wales. Credit: PA

The problem for Labour is none of this, Corbyn fears, fundamentally changes the substance of the Meaningful Vote. And is therefore vulnerable to being more-or-less ignored by whoever succeeds Theresa May as prime minister in the summer.

The account from a Tory source is starkly different: “This Labour line about no changes to the deal is nonsense. True that we didn’t propose changes to the political declaration because they said they wanted legally binding changes and as you know the political declaration is not legally binding.

“But we are very happy to offer changes to the political declaration and we did offer legally binding changes - ie to put certain negotiating objectives in primary legislation. If they want changes to the political declaration they need to move quickly. Any changes need to be approved by the European Council so that’s next Wednesday or June...”

As I understand it, Starmer wants to continue negotiating with the de facto Deputy Prime Minister David Lidington and May’s Chief of Staff Gavin Barwell over the weekend - as do they.

But Labour fears Theresa May has tacked back to placating the Brexiters in her party, which means she is as far from securing parliamentary approval for her deal as ever she was.