It was described on CNN as the "Theresa effect".

When Donald Trump held a joint press conference with Theresa May on Friday, it was a far different performance to his combative display in the Q&A session last month at Trump Tower.

The broadcaster said the president answered questions with "uncharacteristic caution". "During each answer, Trump stopped himself after only a few minutes, moved little beyond what he's said previously, and displayed none of the brashness that became his hallmark on the campaign trail," it said.