Police have been criticised for failing to act as protesters at a rally in London called for “jihad” to “liberate people in the concentration camp called Palestine” Ministers are understood to be “deeply concerned” by the Metropolitan Police’s handling of the incident on Saturday.

Later, the force said that no offence had been identified but that they would talk to one of the men involved to “discourage” such chanting in the future.

At the event, organised by Hizb ut-Tahrir, members of the extremist Islamic group, which both David Cameron and Tony Blair, wanted to ban, bore a banner with the slogan “Muslim Armies! Rescue the people of Palestine”.

In one video clip, a speaker is filmed asking the assembled crowd: “What is the solution to liberate people in the concentration camp called Palestine?”

In response, several men in the crowd are seen chanting “jihad, jihad, jihad”.