London police on Saturday arrested hundreds of protesters for supporting a banned pro-Palestinian group during a demonstration. The protest went ahead despite official requests to cancel it.Authorities had urged organisers to call off the protest after a deadly attack at a synagogue in Manchester two days earlier.Two people were killed in Thursday’s attack in Manchester and police shot dead the murderer, a British man of Syrian origin who investigators believe may have been motivated by extremist Islamist ideology.Despite the appeal from police and the government, organisers refused to cancel Saturday’s march, which had been planned earlier to protest against the banning of Palestine Action under anti-terrorism laws, as reported by news agency Reuters. Prime Minister Keir Starmer in a post on X urged people to respect the grief of the Jewish community.“This is a moment of mourning. It is not a time to stoke tension and cause further pain. It is a time to stand together,” he said.Starmer added that the UK is a nation that welcomes people of all faiths to stand together as neighbours and friends. This affirms that hatred and violence will never prevail.Police made arrests at Trafalgar Square as demonstrators displayed slogans supporting Palestine Action, which was outlawed in July after its members broke into an airbase and damaged military aircraft.By 5.30 pm GMT, police reported 442 arrests about half the number detained at a similar protest in September. Crowds of more than 1000 applauded those being arrested, while others shouted “shame on you” at the officers.“I’m disgusted by the police actually, they shouldn’t be arresting non-violent protesters here,” said Angie Zelter, one of the demonstrators. “We have a right to protest and Palestine Action is not a violent organisation, should never have been proscribed in the first place.”Separately, six people were detained after unfurling a Palestine Action banner on Westminster Bridge near Parliament.Saturday’s demonstration is the latest in a series of rallies where hundreds have been arrested for defying the ban, which makes it illegal to show support for Palestine Action.Police said the protests have drawn police personnel away from strengthened security at synagogues and mosques after the Manchester attack.The protest’s organisers, Defend Our Juries, condemned the attack on the Jewish community and urged police to prioritise community safety over policing demonstrations.The Manchester incident followed a rise in antisemitic and Islamophobic hate crimes across Britain this summer. Pro-Palestinian rallies have also drawn criticism from some Jewish groups.Both Jewish and Muslim communities have expressed growing concern for their safety.