Rishi Sunak has said he will hold the Met Police chief "accountable" over a pro-Palestinian march set to take place this Saturday, on Armistice Day.
The prime minister has criticised the timing of the demonstration in London as "provocative and disrespectful".
Organisers insist their march will not go near commemorations and accuse the government of manufacturing a row.
Protests have been held in London, and other cities globally, each Saturday since the Israel-Gaza war began.
Ben Jamal, of the Palestinian Solidarity Campaign which is behind the march, said he believed the government was manufacturing a row and using the Armistice Day angle to try to "delegitimise" them.
"There's something particularly askew with an argument that says a protest calling for a ceasefire is somehow inappropriate on Armistice Day," he told the BBC.
Home Secretary Suella Braverman has accused the police of being more lax on left-wing protests than those organised by nationalists or right-wing activists.
The home secretary has voiced her opposition to pro-Palestinian protests in the past, calling them "hate marches" in an interview with Sky News.
Protest organiser Chris Nineham, from the Stop the War Coalition, said: "We do everything we can as stewards to make sure there is nothing antisemitic or calling for violence in our demonstrations. For us, this isn't about religion, it isn't about race."
The demonstration on 11 November is due to begin at 12:45, more than an hour after the traditional two-minute silence.
Rishi Sunak is a pawn of the rich who will do anything to distract from the fact that he hates poor people and people who protest.
Well he has to because he hasn't got a clue how to do the job. Remember he lost the election to Truss.
He's what you get when you finish scraping the bottom of the barrel. He's the murky stain that's left behind. Somehow despite the practically subterranean bar he had to clear to be better than his two predecessors, he's managing to be even worse than expected.