Pro-Palestinian protesters staged rallies across Britain including London where a busy rail station and the offices of Labour leader Keir Starmer were targeted.
More than 100 smaller rallies were held across the country with London the host for 10 separate events, including Islington where protesters gather at Mr Starmer's office, and in Tower Hamlets east of the capital.
About 100 pro-Palestinian demonstrators were removed from London's Waterloo station – with other rail stations seeing similar protests – after holding a sit-in demanding a ceasefire in Gaza.
The group chanted: “Free, free Palestine”; “Sit down, join us”; and “From the river to the sea, Palestine will be free” as they protested in the centre of Waterloo.
Police officers surrounded the protesters before they were escorted from the station, with at least two demonstrators carried out.
Hundreds of other protesters rallied outside Mr Starmer's constituency office in Camden, north London, calling for a ceasefire and blocking the road.
Palestinian Nida Badawi told the crowd: “I know we're restless. For the past 40 days, over 40 days, I feel like my heart's been ripped out of my body.
“I'm just here to remind you while we're standing here, it's not the time to stay quiet. They need to hear our voices.”
Earlier in the week, 56 Labour MPs defied Mr Starmer's position of advocating for pauses in fighting so that they could support a ceasefire in a House of Commons vote.
A spokeswoman for the Stop The War Coalition said Saturday’s smaller rallies will be followed by a nationwide demonstration a week later.
“Groups around the country are organising local rallies and marches to basically build for the national demonstration that has been called for next Saturday,” she said.
Ben Jamal, director of the Palestine Solidarity Campaign, said the rallies were aimed to show that “ordinary people” support a ceasefire.
In Glasgow, politicians from the Scottish National Party (SNP), Scottish Labour and the Scottish Greens addressed a crowd of about 18,000 people.
SNP MP Anum Qaisar said: “11,000 people have been massacred in Gaza, almost half of whom are children. Over 1,000 people killed in Israel by the atrocious attack by Hamas. These numbers are rising and they will continue to rise daily unless there's an immediate ceasefire.”
British Transport Police (BTP) said at least five protesters were arrested at Waterloo station.
Sit-in protests were also held at other major UK train stations despite increased policing across railway networks.
Footage shared on social media showed a small crowd sitting on the floor in Manchester Victoria Station, while the force confirmed another group of around 25 had done the same at Leeds station.
The Metropolitan Police said that a “significant” policing operation was planned for the capital this weekend.
They said they would station officers in areas “with significant Jewish or Muslim communities”, which they said “continue to experience increased uncertainty and fear in light of events in the Middle East and their impact here in London”.
Temporary Commander Karen Findlay, who is leading the operation, said: “While there is no single large central protest event on Saturday, our policing priorities remain the same across the local events that are due to take place.
“Regrettably, while the majority of protesters coming out in recent weeks have been peaceful, we have continued to see people taking part in offensive chanting or intentionally carrying placards that cross the line from political statements into racially or religiously aggravated offences,” she said.
The BTP have issued Section 14a orders prohibiting protests on Saturday at many of London’s main rail stations.
The orders will be in place between 10am and 11pm at Waterloo, Charing Cross, King’s Cross, London Bridge, Euston, Liverpool Street, Marylebone, Paddington, Victoria and St Pancras.