The Metropolitan Police imposed strict conditions on the march, warning that anyone who breached them could be arrested.
Deputy Assistant Commissioner James Harman, who leads Met operations including public order policing, said police could not ban the protest unless the risk of serious disorder was so high that it could not be managed through conditions.
"We hear the calls for this event to be banned. The police cannot ban protests and can only ask the Home Secretary to do so if the risk of serious disorder is so high that it can't be managed by conditions. That high bar is not met here," Harman said in a statement Tuesday.
He also rejected claims on social media that the Met had banned other protests, including a UKIP march in Tower Hamlets.
"This will be a day of mourning and reflection for many in London and we know the serious concerns that this event has caused Jewish communities in particular," Harman said.
"We have imposed stringent conditions on those taking part in this march. These will help us manage the event and minimise serious disruption."
Since October 2023, Israeli attacks have killed more than 74,000 Palestinians and wounded over 175,000 in Gaza. About 90% of the territory's infrastructure has been destroyed.
Despite an October 2025 ceasefire agreement between Israel and the Palestinian group Hamas, Israeli attacks have since killed 1,454 Palestinians and wounded another 5,090, according to Gaza's Health Ministry.