A massive demonstration took place in London yesterday, but an accurate number of demonstrators is not known. However, videos documenting the incident clearly show several thousands.

Activists protested the arrest and incarceration of Tommy Robinson, a pro-Israel conservative leader and media personality who has been fighting the phenomenon of Muslim gangs in Britain.

Robinson was arrested two weeks ago while broadcasting on Facebook Live outside a Leeds court where a number of Muslims accused of being part of a rape-grooming gang were tried. He was sentenced to 13 months in prison after a lightning procedure that lasted several minutes, while the court imposed a media blackout on the procedure itself.

Demonstrators clashed with policemen, who retreated at certain points. Five people were arrested and five policemen were injured.

Among speakers was Dutch Freedom Party leader Geert Wilders, who praised Robinson's courage and called for his release. He noted that more than a half-million people had already signed a petition to release him.

Protesters carried signs like "Police State" and "Stop raping our children". They sang Robinson's name again and again, in a melody familiar from soccer fields. Police blocked demonstrators as they approached Buckingham Palace while the royal family was present inside.