Politicians from all parties, Muslim leaders and the public have criticised Scotland Yard for not arresting extremists they accuse of inciting violence. There are calls for Sir Ian Blair, the Metropolitan Police Commissioner, to explain if officers were ordered to adopt a softly-softly approach in dealing with two rallies outside the Danish Embassy in London.

One of the most provocative protests was a demonstrator dressed as a suicide bomber, wearing a fake explosive belt. It is understood that police spoke to the man and two of his associates outside the embassy on Saturday but did not take his name and address.

A man claiming to be the demonstrator, Omar Khayam, a 22-year-old part-time student from Bedford, told a newspaper that he made no apologies wearing the outfit. Describing it as “just a little jacket which you put gadgets in”, he said: “I didn’t go there to cause any harm. I went along just to attend a protest. Did I say ‘Kill Jews’? No. Did I have racist signs on me? No. So why this reaction?” Hizb ut-Tahrir, which organised the weekend protest and which the Government is considering banning, says it has nothing to do with the fake suicide bomber and urged its followers to remain peaceful.

Protest leaders claim that the police gave the go-ahead to carry banners praising Osama bin Laden and the 7/7 bombers. Senior figures at Scotland Yard have told The Times that the priority was to maintain public order and there were fears that had officers tried to make arrests or confiscate banners there would have been violence.

The Yard has been stung by the clamour. Detectives have been studying footage of the demonstrations to try to identify those behind the threats. Some of the faces captured on camera are understood to be militants known to the police who will be questioned. The police said: “Arrests, if necessary, will be made at the most appropriate time and place.”

A police source said: “The hardliners would have loved nothing more than to provoke violence outside the embassy.”

The Shadow Attorney-General, Dominic Grieve, wants the Met to explain its tactics. “I would be very concerned if one was to learn that in fact it’s now proving impossible to detect or identify those who perpetrated this because arrests were not made at the time,” he said.

The Labour MP David Winnick, a member of the Home Affairs Select Committee, said that those who waved threatening placards should be prosecuted.

Sir Menzies Campbell, the Liberal Democrats’ acting leader, said that some of the placards displayed on Friday were “deeply offensive” and gave his backing to the prosecution of anyone threatening violence.

Jack Straw, the Foreign Secretary, appealed for calm as he condemned the burning of Danish embassies but did not comment on the London protests.

Prominent members of the Muslim community expressed their “disgust” at the antics of some protesters. Inayat Bunglawala, of the Muslim Council of Britain, said: “It is time the police acted, but in a way so as not to make them martyrs of the Prophet’s cause, which is what they want, but as criminals. Ordinary Muslims are fed up with them.”

One of the organisers of Friday’s protest, Anjem Choudary, told The Times yesterday that senior officers had inspected the banners before the demonstration began outside the Regent’s Park mosque and made no complaints. “The same officers marched alongside us through London and were present at the embassy and not once did they ask anyone to take down a banner as provocative or offensive.”

Mr Choudary, a solicitor and former leader in Britain of the militant group al-Muhajiroun, refused to criticise the 7/7 banners: “They have to be seen in context. People are angry, but there is a covenant of security and nobody in that protest would advocate attacks here.”

Explore UK News

• Crime News

• Education News

• Health News

• Science News

• Scotland News

Times Recommends

• He’s 65 - Mick Jagger becomes an old man
• Love affair with Labour ends in a Glasgow kiss
• From Moss Side to Rio, theatre saves lives