Fourteen more hostages will be released by Hamas later, as tens of thousands of people prepare to gather in London to call for a permanent ceasefire in Gaza.
Around 1,500 officers will be deployed for the protests, which come amid a temporary truce in the Israel-Hamas conflict and the release of 24 hostages by Hamas.
Egyptian officials confirmed on Saturday that Hamas will later free another 14 hostages in exchange for 42 Palestinian prisoners held by Israel.
Around 100,000 people are expected to march on Saturday from Park Lane to Whitehall, with officers set to hand out leaflets to provide “absolute clarity” on what will be deemed an offence.
The Metropolitan Police will be on high alert in the capital, after a previous rally on Armistice Day saw scenes of violent disorder after counter-protesters clashed with officers.
The force had come under severe pressure from politicians over the decision to allow that march to go ahead, with former home secretary Suella Braverman accusing the force of showing bias in favour of left-wing protesters.
Deputy assistant commissioner Ade Adelekan said that the leaflets set out “that anyone who is racist or incites hatred against any group should expect to be arrested. As should anyone who supports Hamas or any other banned organisation”.
“We will not tolerate anyone who celebrates or promotes acts of terrorism – such as the killing or kidnap of innocent people – or who spreads hate speech.”
Organisers Stop the War Coalition said that such a measure was “intrusive”, but asked anyone attending to avoid “any actions that might leave you or others around you open to arrest”.
“We ask that all attending our marches respect these clear anti-racist principles, including in any signs or placards they choose to bring to the march,” the group said in a statement.
The afternoon will also see a protest by Hizb-ut-Tahrir outside the Egyptian Embassy. It is the first by the group since October 21, after a video emerged showing a man chanting “jihad”.
The Met said no offences were identified from the clip, but it prompted an outcry from politicians.
Ahead of Saturday, Mr Adelekan said chants using the word “jihad” were causing upset and concern in the Jewish community but were “always contextual”.
A 90-minute march organised by the charity Campaign Against Antisemitism is also due to take place on Sunday, with around 40,000-50,000 people expected to attend.
New Home Secretary James Cleverly said he expected the Met Police to address the concerns from the Jewish community.
“When a minority in the UK are screaming at us that they are scared beyond belief by what is happening it is incumbent upon UK policing and politicians to listen and respond,” he told the Times.
“What we saw over the last few weeks is the Jewish community in the UK telling us over and over and over again they felt vulnerable.
“The police have to respond to that. In the conversations I have had with senior police officers in the Met and more broadly and in the conversation I had with the mayor of London I’ve made clear it is my expectation that they address those concerns.”
On the first day of the four-day ceasefire, Hamas released 24 of the about 240 hostages taken during its October 7 attack on Israel that triggered the war, and Israel freed 39 Palestinians from prison.
Those freed from captivity in Gaza were 13 Israelis, 10 Thai nationals and a citizen of the Philippines.
Under the agreement, Hamas will release one Israeli hostage for every three prisoners freed.
Foreign Secretary David Cameron used a two-day trip to the region to warn Benjamin Netanyahu’s government that Israel’s long-term security depends on the Palestinians also being able to live in “peace and stability and security”.
He told the BBC: “Ultimately, there won’t be long-term safety and security and stability for Israel unless there is long-term safety, security and stability for the Palestinian people.
“And you have to start thinking about the future… You’ve got to paint a picture of actually the Palestinians living in peace, stability and security.”
