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.
From my Canadian vantage point it seems Britain needs a raft of new politicians who aren't rich dumbfucks.
Mind you the same thing can be said for almost every nation rn … including mine.
Same from my vantage point in Denmark, on all counts 😕
At this point I think we would honestly be better off being led by actual fascists. It wouldn't make any difference politically but at least they would admit it.