The "National March for Palestine" is the fourth to be staged in the British capital since the Oct. 7 Hamas attacks on Israel, but ministers have said it should to be cancelled as it coincides with Armistice Day, which marks the end of World War One, and commemorations for those killed in military action.

Police have said they will have almost 2,000 officers on duty, vowing to crack down on any disorder caused either by those involved in the march or a counter-protest by opposing right-wing groups and veterans.

"I do believe if the groups come together, there will be serious disorder," said Deputy Assistant Commissioner Laurence Taylor, the officer in charge.

"The policing operation this weekend is huge," he told reporters, saying it would be "challenging and tense".

There has been strong support and sympathy for Israel from Western governments, including Britain's, and many citizens over the Hamas attacks. But the Israeli response has also prompted anger, with weekly protests in London demanding a ceasefire.

Organisers from the Palestine Solidarity Campaign have said Saturday's march will steer clear of the Cenotaph war memorial near Sunak's Downing Street office, and will conclude at the U.S. embassy about two miles away.

Police have said they would impose an exclusion zone around areas connected to remembrance events, while an unprecedented 24-hour police guard at the Cenotaph has been in place since Thursday.

"We could have one of the biggest marches in British political history potentially, but I would confidently say hundreds of thousands will be attending," Ben Jamal, the PCS Director, told Reuters.

"Politicians can only ignore significant bodies of public opinion for so long."

'HATE MARCHERS'

While previous PSC marches have been generally peaceful, there have been more than 100 arrests for offences including showing support for Hamas, which is banned as a terrorist organisation in Britain, or holding placards with offensive slogans.

Three women appeared in court on Friday charged with terrorism offences for supporting Hamas by wearing paraglider images, and police say the behaviour of breakaway groups at the rallies has become more violent.

Home Secretary Suella Braverman, the minister in charge of policing, has courted controversy by calling the protesters "hate marchers", and Sunak has come under pressure from his own lawmakers to sack her after she accused the police of double standards over how they treated "pro-Palestinian mobs".

The prime minister himself has said Saturday's protest was disrespectful, but should be allowed to go ahead, although he said he would be holding London's police chief accountable for safeguarding remembrance events.

Lawmakers have voiced concern that far-right groups will seek to use the occasion as an excuse for violence.

Stephen Yaxley-Lennon, the former co-leader of the English Defence League, which staged often violent demonstrations against Islam, has called for his supporters to mass in the capital.

"We want to show the world that the British people ain't having it," Yaxley-Lennon, who goes by the name of Tommy Robinson, said on a social media video. "So ... I hope this Saturday I see as many of you as possible in London."

DAC Taylor said police were hoping to prevent trouble, but clashes were likely.

"There will be times this weekend where you see pockets of confrontation, despite the conditions and everything that I've put in place to manage that," he said.

"I hope we don't, but I think it's likely you will see police having to use force to manage some of the situations that we have to deal with."