A 13-year-old girl who was arrested at a “yellow vests” protest in support of Brexit was released pending investigation on Saturday night.
The teenager had been detained on suspicion of assaulting a police officer as demonstrators took to London’s Westminster Bridge.
Protesters donned yellow hi-vis jackets, emulating the “gilets jaunes” demonstrations that originated in France.
Scotland Yard said: “Four arrests have been made following protests on Westminster Bridge, SW1 at approximately 11am today.
“Three men arrested on suspicion of public order offences. A 13-year-old girl was also arrested on suspicion of assault on police. Inquiries continue.”
Demonstrators were seen burning an EU flag while chanting: “Stick your flag with stars on up your arse.”
Others sang: “We want Brexit. When do we want it? Now.”
Smoke bombs were also seen strewn across Westminster.
The protest came about a month after thousands descended on the capital for a “Brexit betrayal” march led by the controversial activist known as Tommy Robinson and Ukip.
Counter-demonstration organisers Momentum at the time claimed to have “vastly” outnumbered Mr Robinson’s fans nearly five to one by amassing some 15,000 supporters.
However, Scotland Yard estimates revealed on Saturday after a Freedom of Information request suggested about 5,000 turned out in support of the pro-Brexit march, whereas counter-demonstrators numbered approximately 1,000.