The decision was made two months ago, but I think the written opinion has just become available, as GW v. An Immigration Officer. Note that the decision rests in considerable measure on internal European Union regulations having to do with freedom of movement among European states:
As a result of the 2006 Regulations, introduced by the present government, a Dutchman has almost the same right to visit London as a Yorkshireman has; and as a result of the Human Rights Act 1998, a Dutchman has the same right of freedom of expression as a Yorkshireman has.
The tribunal’s interesting discussion of freedom of expression, and of the insufficiency of the government’s threat-of-disturbance rationales, has to be understood against that backdrop.
(Note also, for whatever it’s worth, that the First Amendment, as interpreted by the U.S. Supreme Court, allows the U.S. government broad authority to exclude visiting aliens based on the content and viewpoint of their speech, even if the speech is constitutionally protected. I express no opinion here about whether that constitutional rule is right or wrong; I just wanted to preclude arguments that the initial decision in this case was somehow a sign of how the UK provides substantially lesser free speech protections than the US — that’s true in some instances, but not in this one.)