(As usual, he got his facts wrong, but what else is new?)
In tweets of their own, London Mayor Sadiq Khan and former opposition leader Ed Miliband offered a different interpretation: "Many Londoners have made it clear that Donald Trump is not welcome here while he is pursuing such a divisive agenda. It seems he’s finally got that message." (Khan) and "Nope it’s because nobody wanted you to come. And you got the message." (Miliband).
Boris Johnson (Foreign Secretary, sometimes known as "BoJo") couldn't resist sticking up for Trump (maybe they've bonded over their hairstyles?), tweeting: "The US is the biggest single investor in the UK - yet Khan & Corbyn seem determined to put this crucial relationship at risk. We will not allow US-UK relations to be endangered by some puffed up pompous popinjay in City Hall."
News flash, Boris -- the "puffed up pompous popinjay" currently resides at 1600 Pennsylvania Avenue in Washington, DC.
Theresa May, who still has that very ill-advised early invitation to Trump to make a state visit to Britain hanging around her neck like an albatross, appears to be studiously silent.
I'm guessing that the embassy staff is heaving a collective sigh of relief, and I don't blame them.