Charles Clarke, the Home Secretary, gave a strong signal to the police to proceed with the prosecution of Muslim protesters who called for people to be beheaded or massacred over the publication of offensive cartoons of the Prophet Mohamed.
Mr Clarke, who met the Parliamentary Labour Party yesterday, faced anger from his own MPs over the failure of the police to act against the protesters. But in a Commons statement he made it clear that the Government would support any prosecutions if the police and the Crown Prosecution Service took action.
"They are undertaking rigorous assessments as the appropriate way to proceed in individual cases," he said. "If the police decide there have been breaches of the law and take action, we would support them."
The Metropolitan Police yesterday promised an urgent and swift inquiry, headed by a detective chief inspector, in the public order crime unit. Senior officers will examine everything, from video recordings made by officers to photographs published in newspapers.
A student who wore a "suicide vest" in Friday's protest issued a full apology yesterday. Omar Khayam, 22, said that he apologised " wholeheartedly" to the victims and families of those attacked on 7 July for the offence caused by dressing as a suicide bomber.
The part-time construction student a convicted drug dealer jailed in 2002 for five-and-a-half years for dealing heroin and cocaine, but who has since been freed on licence said that he dressed in the military-style webbing because he had found the cartoons showing the Prophet "deeply offensive". But as he became the subject of increasing media interest, he realised his actions had been wrong.
Speaking outside his home in Bedford while flanked by his MP, Patrick Hall, and the chairman of a local mosque, Mr Khayam said: "My method of protest has offended many people, especially families of the victims of the July bombings.
"I do not condone these murderous acts, do not support terrorism or extremism and would like to apologise unreservedly and wholeheartedly to the families of the victims. I understand it was wrong, unjustified and insensitive of me to protest in this way."
Mr Clarke sought to use the protests to challenge opponents of the Government's Terror Bill to drop their opposition to some of the most controversial proposals including a clause to outlaw the "glorification" of terrorism, which was thrown out in the Lords. His remarks are certain to intensify the row over the Bill when it returns to the Commons next week.
Ministers appeared to harden their rhetoric after calls grew for prosecutions over the demonstrations in London, with the police accused of standing by while protesters carried banners that appeared to incite people to murder.
Mr Clarke called on the Tory leader David Cameron to drop opposition to a clause outlawing glorification of terrorism. But Mr Cameron later appeared to rule out any compromise over the plans.
Asked if he would back the law, he said: "I believe in free speech, but free speech under the law. Many of those people carrying those placards were clearly inciting violence or inciting hatred and that is against the law. It does not need any new glorification laws. The things they are inciting people to do are against the law today."
Labour rebels, who are determined to stick to their objections, are also likely to accuse Mr Clarke of using the offensive protests last week to drive through a measure which will damage civil liberties. However, it is likely that the Government will overturn the Lords defeat and reintroduce "glorification" of terrorism as a new offence.
Officials said it would enable the prosecution of Muslim clerics who have avoided directly inciting supporters to kill people, but suggested that those who carried out killings would enter heaven. Senior Whitehall sources confirmed that protesters who last weekend directly called for people to be killed could be prosecuted under the existing incitement to murder laws.
The Government appeared ready to support prosecutions but both Mr Clarke and the Prime Minister's official spokesman went to great lengths to distance themselves from a decision to prosecute, saying it was a matter for the police and the Crown Prosecution Service.
The Home Secretary condemned the violence aimed at European embassies and Danish citizens but caused frustration on his own side by refusing to publicly back the prosecution of the protesters. David Winnick, an outspoken Labour backbencher, said: "It is entirely unacceptable for a bunch of hooligans and thugs in London to demand that people be beheaded. They glorify the atrocities of 7 July and call for further atrocities to be committed."
He added: "The message should go out that never again on British soil will we see the kind of slogans and incitement to murder that so disgraced this country last Friday."
But lawyers warned the Government not to try to make any political capital out of the demonstrations.
Shami Chakrabarti, director of the human rights group Liberty, said this was not the time to have this kind of debate. "The law surrounding the curtailment of free speech has grown up through ad hoc responses to a series of public outrages over the years. There is an awful lot of it, some of which has been abused in the past."
She said that the real danger to free speech was the "chilling effect" of some of this legislation, including the proposal for the glorification of terrorism, which meant people would become too afraid to voice legitimate criticism in public.
Hugo Charlton, a barrister who worked on the anti-poll tax campaign and has advised animal rights activists and protesters against the war in Iraq, said he was opposed to knee-jerk reaction to the cartoons row.
He said: "We all need to remain calm what we don't want is more legislation that might be misused at other times. The media has a very important role to play in what happens next.
"The newspapers have to ask themselves whether they think they have contributed to the problem or helped to resolve matters. I don't think they have covered themselves in glory."
Freedom of speech in Britain today: How the legislation is applied
* OMAR KHAYAM
Who? Muslim protester who took part in demonstrations outside the Danish embassy last week.
What he said: Gave the impression he was a suicide bomber by wearing a jacket with dynamite pouches.
What happened? Apologised for his actions but faces an investigation by the police.
* NICK GRIFFIN
Who? Leader of the British National Party.
What he said: In a speech to BNP supporters, which was secretly recorded by the BBC, he described Islam as a "wicked, vicious faith".
What happened? He was acquitted by a jury last week of inciting racial hatred.
* SIR IQBAL SACRANIE
Who? Secretary general of the Muslim Council of Britain.
What he said: Claimed that homosexuality and Islam were incompatible.
What happened? He was investigated by the police for allegedly making homophobic remarks. The case was dropped on the advice of the Crown Prosecution Service.
* MAYA EVANS
Who? A 25-year-old peace protester.
What she said: Read the names of the (then) 97 British soldiers killed in the Iraq conflict, at the Cenotaph in Whitehall.
What happened? Ms Evans was given a conditional discharge and ordered to pay £100 costs.
* WALTER WOLFGANG
Who? Octogenarian and member of the Labour Party.
What he said: Shouted "nonsense" as Jack Straw defended Britain's role in Iraq at last year's Labour Party conference.
What happened? He was bundled out of the conference and later stopped under anti-terrorist powers as he tried to re-enter.
* BRIAN HAW
Who? A campaigner against the war in Iraq who lives in Parliament Square.
What he said: Claims Labour is responsible for Britain fighting an illegal war.
What happened? The Government banned demonstrations within 1km of Parliament. The courts have since ruled the law does not apply to Mr Haw.Reuse content