Thousands have marched in London and Edinburgh as pro-Palestine demonstrators called for an immediate ceasefire in Gaza. Saturday’s marches were the UK’s first national demonstrations since the UN’s international court of justice ordered Israel to ensure acts of genocide are not committed in Gaza. About 10,000 marched in London on Saturday. Along with other protesters, Jewish groups backed calls for a ceasefire, displaying banners calling for the Israeli leader, Benjamin Netanyahu, to secure a hostage deal and chanting: “Netanyahu, shame, shame, not in our name.” Other protesters carried banners that read: “End the killing”, “Free the children”, “Freedom to Palestine” and “Boycott Israel”. Thousands of pro-Palestine supporters also gathered in Edinburgh on Saturday in support of an immediate ceasefire in Gaza. Arranged by the Scottish Palestine Solidarity Campaign, spokesperson Mick Napier said: “Israel needs to act on last week’s Order of the World Court, which requires that it take measures to prevent further genocide, and stop preventing aid getting to the 2 million people of Gaza. The only way that is possible is with an immediate ceasefire, which is what we are calling for. While the Scottish Parliament has at least called for a ceasefire, the UK government, as usual, has been entirely complicit in Israel’s crimes.” In London, Scotland Yard estimated about 10,000 demonstrators had marched through the West End, with the crowd swelling to 20,000 for the speeches in Whitehall. BBC reports described the atmosphere as “peaceful”. Police said people were seen trying to disrupt the protest in Haymarket and a woman was arrested on suspicion of setting off a smoke bomb or flare. A second woman, who was allegedly chanting slogans that may incite racial hatred, was arrested over a suspected public order offence. Organisers had expressed concerns that the Metropolitan police would take a harsher approach compared with previous demonstrations, accusing the force of bowing to political pressure from the government to restrict the marches. The Met said officers monitored the march for offensive placards, chants and banners and that it used CCTV to spot other offences and find suspects. It had previously announced officers would be authorised to demand the removal of face coverings they believed were being worn to conceal a person’s identity, throughout the borough of Westminster, from 10am on Saturday to 1am on Sunday. The force said this measure would not apply to religious face coverings. Chris Nineham, the vice-chair of Stop the War, said: “This is yet another example of the police attempting to criminalise Palestine protests and in the process chipping away at civil liberties. They are deliberately trying to raise tensions and to create the impression that people marching for peace and an end to a genocide are a threat to society. It’s an absolute disgrace.” After having told organisers on Wednesday the Met would not allow demonstrators to end with a rally on Whitehall, where marches have regularly ended, the force made a U-turn on Thursday and said the march could end near Downing Street. A request for two end rallies, including one in Trafalgar Square, was denied, however, with the Met saying they would have hundreds of officers on duty but fewer resources than on previous march days to police the protests. In a statement, the force said: “The vast majority of those joining protests have done so in a lawful and peaceful way but a minority have broken the law and arrests have been made [at previous marches].” Deputy assistant commissioner Matt Ward, who is leading the policing operation, said: “We respect the right of people to protest, but other Londoners and visitors have rights as well. “I understand the cumulative impact of repeated protests since October on businesses, residents and those who want to travel into the West End. Getting the balance between competing rights can be difficult, but we will do it independently, impartially and always within the law.” Just over a week ago, the international court of justice ordered Israel to ensure its forces did not commit acts of genocide against Palestinians in Gaza. In an interim judgment, the president of the court, Joan Donoghue, said Israel must “take all measures within its power” to prevent acts that fall within the scope of the genocide convention and must ensure “with immediate effect” that its forces do not commit any of the acts covered by the convention. Earlier in January, the Palestine Solidarity Campaign organised a march of hundreds of thousands of people through central London. Little Amal, a 4-metre puppet of a Syrian child refugee, accompanied protesters as they marched towards Parliament Square. The following weekend, hundreds joined a multi-faith peace march in solidarity with people affected by the conflict. The Gaza health ministry says at least 27,131 Palestinians have been killed and 66,287 have been injured in Israeli strikes on Gaza since the 7 October Hamas attack on Israel, in which 1,200 people were killed and about 250 abducted. Satellite images analysed by the UN Satellite Centre show that 30% of Gaza Strip’s buildings have been destroyed or damaged. Unicef estimated on Friday that 170,000 children in Gaza were unaccompanied or had been separated from their families. Saturday’s demonstration was the eighth National March for Palestine organised by the Palestine Solidarity Campaign since October. This article was amended on 3 February 2022. An earlier version stated incorrectly that the Met police had banned face coverings in Westminster from 10am on Saturday to 1am on Sunday.