The leader of the far-right nationalist English Defence League, Stephen Lennon, was arrested during Saturday's march in London, along with 150 anti-fascist demonstrators who had turned out to oppose his protest.
Lennon, who styles himself "Tommy Robinson" among other aliases, led 500 EDL members on the march - far short of the 2,000 he had anticipated - but his supporters quickly found themselves outnumbered by thousands of activists from left-wing groups such as Unite Against Fascism and Hope Not Hate.
Police used tear gas and kettled protesters in Tower Hamlets, East London, as they tried to prevent violent clashes between the rival groups.
Those on the EDL march were prevented from entering parts of the borough, which is home to a large Muslim community, and came up against heavily manned police lines.
A police spokesman said about 150 mainly left-wing activists were arrested for breaching section 12 and section 14 of the Public Order Act, after a breakaway group attempted to march on Tower Bridge, where the EDL planned to end its march.
Lennon was arrested for inciting others to break the conditions set for the protest, he said later on Twitter.
Another 14 activists, mainly EDL members, were arrested for violent disorder and possession of knives and fireworks.
EDL supporters had marched over Tower Bridge before being halted at Aldgate.
They had been banned from marching through the borough of Tower Hamlets to the East London Mosque by a High Court ruling.
The Metropolitan Police had argued that the event could cause "serious public disorder".
The lawyer for the EDL, Jamas Hodivalatold, told the court the group chose Tower Hamlets because they believed the area had become "subject to Sharia law".
Yesterday's event was marked by skirmishes between anti-Nazis and EDL supporters, during which police came under a barrage of bottles and flares.
But a police spokesman said the high police presence meant serious violence had been averted. About 3,000 officers were deployed to police the event.