Tens of thousands of people marched through central London on Saturday in two large, concurrent demonstrations held on opposite sides of the city, as the Metropolitan Police mounted one of its biggest public-order operations of the year.
Police estimated that about 50,000 people attended a "Unite the Kingdom" march led by the activist Tommy Robinson, while organisers of a separate pro-Palestinian rally marking Nakba Day expected around 30,000 participants in South Kensington.
Around 4,000 officers were on duty, supported by armoured vehicles, mounted police, dogs, drones and helicopters. The force put the cost of the operation at roughly £4.5 million.
The Metropolitan Police said 11 people had been arrested by early afternoon "for a variety of offences" across both events. Among them were two men wanted in connection with a hit-and-run in Birmingham, who were detained as they tried to join the Unite the Kingdom march.
A woman at the pro-Palestinian demonstration was arrested after refusing to remove a face covering. Marchers on that side of the city carried Palestinian flags and placards, while those at the Unite the Kingdom event waved Union flags.
The competing rallies underscored the continued tension in Britain over immigration and the war in the Middle East, issues that have driven a series of large and sometimes confrontational demonstrations in the capital over the past year.