Maxperson
Morkus from Orkus
The UK has no problem with free speech. They have a problem with any political personages whose speech they deem detrimental to international relations between their country and ____________. That's one way diplomats get ejected.
Trump, as a candidate for the highest political office in the UKs most important ally, has proven himself to be someone they don't feel comfortable talking to in a political dialog. So they're keeping him out.
A subtle message from them to us.
And it's a message that they'd eat with some tea if he got elected. I doubt they would alienate the U.S. over it.