Difficult day for prime minister but not a disaster

Well. However she did it, Theresa May managed to roll Donald Trump back from the outright and overt criticism of her, and her most important policy, before their press conference today.

Rather in the manner of a boss telling staff who'd been caught bunking off that they would work extra hours, almost the first words out of the prime minister's mouth were that he did actually agree that the UK and the US would sign a trade deal after Brexit, and enthusiastically so.

The president was not quite so effusive in his statements and betrayed frankly what many members of the public feel about the government's Brexit plans - "I don't know what they're going to do but whatever you do is ok with me".

• LIVE: Latest updates on Donald Trump's UK visit

But he did, it seemed obediently, crank out the prepared line from his notes that the US was committed to doing a deal. Between now and next March you can bet you'll hear those remarks used as evidence by the prime minister of the UK's exciting future outside the EU again, and again, and again, oh and again.

I'm sure you can picture the scene - whether an MP or a journalist asks, 'Prime Minister, this deal means it will be hard to do other trade deals', 'Donald Trump said the contrary, that the US was committed to work to seize the opportunities with a comprehensive deal'.

That doesn't mean that's what will happen. Off script the president's doubts were pretty clear that for a trade deal to work the UK can't sign up to many restrictions. And while she denied it today, the prime minister and her colleagues well know that agreeing the 'common rule book' as we've discussed so much in the last week or so, does make the UK a less attractive trade partner for other countries.

Indeed in officialese the government's own documents acknowledge as much. It is a decision that she has taken, that Donald Trump might not like much, but she has taken it for a reason.

For the choreography of today though to be just awkward, not downright cringeworthy, it was important for Number 10 to pull Donald Trump back from his previous statements.

He, true to form, tried to pretend that he hadn't really said what he said, even though his remarks were made on the record. 'Fake news', it was not. That is important to understand, because it means that the difficulties between our two countries over a tighter trading relationship have not disappeared.

And for Theresa May, the bigger problem is that many in her party agree with him, not his world view, but the fact that her Brexit compromise could cut off some of what Leavers saw as the greatest possibilities of leaving the EU.

This was a difficult day for the PM for sure, but not a disaster. But at a time when she desperately needs friends and allies, the American president is not necessarily one upon whom she can totally rely.