Far-right Dutch MP Geert Wilders has won an appeal against a Home Office decision barring his entry to the UK.
The Asylum and Immigration Tribunal ruling overturns a government decision that led to Mr Wilders being turned back at Heathrow in February.
The Freedom Party leader, who has been accused of Islamophobia, planned a UK visit next week, his solicitor said.
The Home Office said it was disappointed, and would decide in "due course" whether to fight the ruling.
A spokesman said: "We are disappointed by the court's decision. The government opposes extremism in all its forms.
"The decision to refuse Wilders admission was taken on the basis that his presence could have inflamed tensions between our communities and have led to inter-faith violence. We still maintain this view."
BBC home affairs correspondent Danny Shaw said that a further appeal by the Home Office or a new ban on different grounds were possible.
The Home Office will need Court of Appeal permission to keep the travel ban in place pending any appeal.
Mr Wilders faces trial in his own country for inciting hatred.
The refusal to admit him to the UK in February prompted "a very heated debate at the time", our correspondent added.
"There were people that said, 'Look, we don't like his views. His views may be unpleasant, they may be something we don't agree with - but he should be allowed in to express those views and show his film, and we can argue and debate with him.'
"There were others that said, 'It would actually inflame tensions. This is not the kind of person that we want to have.' That was very much the line that the government said at that time."
Mr Wilders' lawyer, Tiki Emezie, said his client was "very happy" at the ruling, and would attend a meeting with the UK Independence Party's Lord Pearson in London next week.
In February, he had been invited by Lord Pearson to the House of Lords to show his controversial film Fitna, which caused outrage across the Muslim world when it was posted on the internet last year.
When he was refused entry, Mr Wilders told the BBC it was a "very sad day" for UK democracy.
"I'm not doing anything wrong. I'm not protesting or running through the streets of London," he said.
"Democracy means differences and debate. It's a very sad day when the UK bans an elected parliamentarian."
Lord Pearson said it was a "matter of free speech", telling the BBC: "We are going to show it anyway because we think MPs and peers should see this film."
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