May 2013 Last updated at 12:01 ET
Woolwich murder: Government defends security services
- Woolwich aftermath as it happened
- The investigation
- Security services knew suspects
- Killed soldier was 'loving father'
The UK government has defended security services against criticism they missed signs which might have helped prevent the murder of a soldier in London.
The security services face a Commons inquiry after it was confirmed the two men arrested over the murder of Drummer Lee Rigby were known to MI5.
But Communities Secretary Eric Pickles said it was impossible to control everyone all the time.
Michael Adebolajo and Michael Adebowale were named as suspects.
Mr Pickles told the BBC: "Peers and MPs will do a thorough investigation in terms of what the security forces knew but I've seen experts on security explaining how difficult it is in a free society to be able to control everyone."
Drummer Rigby, 25, was murdered on a street in Woolwich, south-east London on Wednesday afternoon.
Shortly after the killing, a man, thought to be 28-year-old Mr Adebolajo, was filmed by a passer-by, saying he had carried out the attack because British soldiers killed Muslims every day.
Armed police arrived on the scene 13 minutes after the first 999 call and shot the two suspected attackers, who had made no attempt to flee.
Footage of shooting
More than 30 people attended a prayer service in Drummer Rigby's hometown of Middleton, Greater Manchester on Friday morning. Residents on the Langley estate where he grew up are being urged to fly union jacks by community activists.
Drummer Rigby had served in Afghanistan, Germany and Cyprus.
The former head of counter terrorism at MI6, Richard Barrett, told the BBC how hard it could be to detect attacks of the type seen in Woolwich - despite the suspects having been known to MI5 for eight years.
"I assume that these people are probably coming out of a small group without, necessarily, any overseas connections or any other broader connections in the United Kingdom which could come to the attention of the security services more than they did," he said.
"When does a person who expresses radical views, who joins a radical group, flip over to be a violent extremist?
"To find the signals, the red flags as it were, I think is enormously hard."
Former Metropolitan Police commissioner, Lord Blair, told BBC radio he hoped the committee investigating how the suspects were monitored "would act fast" to establish what might have gone wrong.
"I think it's important for the public to have somebody say within the limits of legality that either something was mistaken, either decisions were badly taken or they weren't, because I think it's important for the public to know security services and the police are operating properly," he said.
His comments came as video footage, obtained by the Daily Mirror, emerged showing the moment police shot Mr Adebolajo, originally of Romford, east London, and Mr Adebowale, 22, of Greenwich, south-east London.
It shows one of the men charge at police sitting in a patrol car. He drops a knife as he is shot and falls to the ground.
- Drummers are musicians as well as fully trained fighting infantrymen
- Can be deployed to any area in the world within 24 hours
- Given drum training, and play drum scores relevant to their regimental tunes
- Some can also play the bugle
The other man is shown aiming a gun at officers as he runs in a different direction. Police are heard firing eight shots in total at the two men.
Both of the suspects remain under armed guard in separate London hospitals in stable conditions with non-life-threatening injuries.
And police are said to be standing guard outside Mr Adebowale's home in Greenwich, according to BBC correspondent Tom Bateman.
Detectives are also interviewing a man and a woman at a south London police station after they were arrested on Thursday night on suspicion of conspiracy to murder.
'Solidarity against extremism'
The BBC has uncovered its own footage of Mr Adebolajo taking part in an Islamist demonstration in April 2007 against the arrest of a man from Luton, holding a placard reading "Crusade Against Muslims".
He is shown standing next to then-leader of the now banned al-Muhajiroun organisation, Anjem Choudary, who has said Mr Adebolajo went his own way in around 2010.
Mr Choudary appeared on Newsnight on Thursday and said Mr Adebolajo had made comments that "I think not many Muslims can disagree with".
The radical Islamist preacher said he was "shocked" by what had happened. He also said: "One man killed in the street does not equate to the hundreds and thousands and millions, in fact, who've been slaughtered by the British and American foreign policy."
Meanwhile, thousands of members of the Ahmadiyya Muslim community are expected to gather in London to offer prayers for the dead soldier and his family and to "express solidarity against extremism".
National president Rafiq Hayat said: "We hope that the perpetrators of this crime, that is based on a twisted and warped ideology, are brought to justice."
On Thursday, Drummer Rigby's family paid tribute to "a loving son, husband, father, brother, and uncle, and a friend to many".
They said in a statement that Drummer Rigby, who had a two-year-old son, "would do anything for anybody - he always looked after his sisters and always protected them".