Thousands of people took to the streets in central London in a “Brexit betrayal” protest led by Tommy Robinson and Ukip.
Counter-demonstrators and anti-fascists held a separate protest they claimed had drawn some 15,000 people, although there has been no official crowd size estimates.
The Metropolitan Police mounted a significant public order operation to prevent potential disorder but only three arrests had been made - all of counter-protesters - by the time both rallies ended.
Robinson, the English Defence League (EDL) founder who has been welcomed into the Ukip fold as an adviser to leader Gerard Batten, hinted he could run as a Ukip MP.
Speaking at the Brexit "betrayal" rally, he said that after watching MPs criticise him in parliament he "thought one day I'll be sitting in there amongst you".
Ukip’s official event page for the Brexit march said it would be “a democratic and peaceful demonstration expressing the strength of feeling amongst Leavers”.
The party is looking to gain fresh momentum following a wave of resignations from MEPs and high-profile figures, including Nigel Farage, over Robinson’s appointment and Mr Batten’s focus on Islam.
Robinson, whose real name is Stephen Yaxley-Lennon, gave a speech at the march alongside controversial YouTubers who have been welcomed into Ukip in recent months.
The EDL founder noted that he did not want to be seen to "jumping on the Brexit bandwagon" but that his supporters "need a political voice".
He also called for a mass Ukip membership drive asking his supporters to join the party.
Mr Batten described getting Robinson talking about Brexit as being a "huge success".
“I’ve persuaded Tommy Robinson to talk about Brexit, that’s what he will be talking about. Brexit and the EU will be the only subjects on the agenda at that rally," he said last week.
“We want as many there as possible to show you’re opposed to this withdrawal agreement, we want to dump the deal.”
Around 1,300 people have pledged to attend on Facebook and the number of marchers are not expected to approach the hundreds of thousands who demonstrated for a Final Say referendum on Brexit in October.
The Metropolitan Police imposed strict conditions on the “Brexit betrayal” march and counter-protests in efforts to keep opposing demonstrators apart.
Police warned that anyone breaking restrictions under the Public Order Act, which require protesters to stay within designated areas and leave by a stated time, would be committing a criminal offence and would be arrested.
Scotland Yard said the move was proportionate based on “current tensions and concerns”, intelligence and the violence seen at Free Tommy protests in the summer.
“The right to protest is a fundamental right in our democratic society, but this right must be balanced against the right of people to go about their day without fear of violence, disorder or disruption,” said Deputy Assistant Commissioner Laurence Taylor.
”Experience has shown us that when groups with conflicting views come together it can create tension and disorder, not just on the day itself but in the longer term."
See below how we covered this story live
Met Police bracing for disorder at Brexit 'betrayal' march led by Tommy Robinson as protesters praise France's yellow vests
'We’ll be there for a couple of hours and then go home in an orderly fashion,' Ukip leader Gerard Batten saysThe march must take place between 12.30pm and 2pm, and the rally must end by 3.30pm.
The march must end by 1.15pm and a rally in Whitehall, near Trafalgar Square, must end by 4.30pm.
What is the Brexit Betrayal Rally?
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Support for remaining has grown steadily since the summer and jumped three points in December“Experience has shown us that when groups with conflicting views come together it can create tension and disorder, not just on the day itself but in the longer term. We have had to carefully consider how to balance the right to protest with the potential impact on our communities and our ability to manage any disorder that may have resulted from these protests going ahead as they were suggested.
“If you want to protest on Sunday we ask that you do so peacefully, no matter what your view. We will adopt a robust arrest policy on anyone who attends and is intent on violence and disorder, or is in breach of these conditions.”
Here are details of conditions imposed on both the Brexit 'betrayal' march and counter-demonstrations by the Metropolitan Police
Conditions imposed on march and rallies in central London
Conditions have been imposed on the Brexit Betrayal march and rally and a counter march and rally by Oppose Tommy Robinson in London and Unite Against...
Met Police bracing for disorder at Brexit 'betrayal' march led by Tommy Robinson as protesters praise France's yellow vests
'We’ll be there for a couple of hours and then go home in an orderly fashion,' Ukip leader Gerard Batten says
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