A group of Tommy Robinson supporters has blocked off a major road in central London in a tense stand-off with police, who made several arrests.
Hundreds of demonstrators descended on the capital and blocked off the road around Trafalgar Square.
Rows of riot police blocked the gate down the Mall leading to Buckingham Palace, where the Royal Family has gathered on the balcony after celebrating Trooping the Colour just hours earlier.
The protest on Saturday afternoon was the latest in what appears to be a bid to secure the release from jail of the former leader of the English Defence League (EDL).
Supporters chanted “Free Tommy Robinson” and hurled missiles and smoke bombs at police.
Hundreds of supporters crowded on to an open-top sightseeing bus, waving union flags, while one supporter posed on the roof in a Donald Trump mask.
By 6pm, officers had removed protesters from the bus and had kettled many of the remaining protesters on the traffic island overhead.
Other Robinson supporters crowded on to the steps of Nelson’s Column and continued to chant slogans.
A spokesperson for megasightseeing.com said: “Our London sightseeing bus was on its normal route when it got caught up in the demonstrations. The bus was stormed by demonstrators, and the driver and a small number of customers got off.
“The demonstrators have caused a significant amount of damage to the bus, which meant it had to be towed away. We have reported this to the police, and will help them with any investigations.”
Videos posted on social media appeared to show police being significantly outnumbered by demonstrators.
The Met said that as of 6.30pm, one person had been arrested for possession of an offensive weapon, two for assault on a police officer, a fourth for possession of a flare and a fifth for criminal damage to a bus. The Met will now look at CCTV footage of the demonstration.
Robinson was jailed for contempt of court after he used social media to broadcast details of a trial which is subject to blanket reporting restrictions.
Leeds crown court heard how Robinson filmed himself and people involved in the case, in footage that was watched around 250,000 times within hours of being posted on Facebook.
Robinson, who was listed by his real name Stephen Christopher Yaxley-Lennon on court documents, was sentenced to 13 months in jail on the same day as his arrest.
He was given 10 months in jail for contempt of court, and an additional three months for breaching a previous suspended sentence.