Detectives investigating the brutal killing of Drummer Lee Rigby arrested three further men last night on suspicion of conspiracy to commit murder.
Two men aged 24 and 28 were arrested at a house in south-east London, while a 21-year-old man was arrested in Charlton Lane, Charlton.
Police used tasers to detain two of them.
The arrests came as ministers were accused of "retreating" from a campaign to stop young people drifting into the clutches of extremists. Hazel Blears said the Prevent strategy, drawn up by the Labour government to steer thousands of youngsters away from violent extremism, had been allowed to wither due to dwindling funding and political will since the coalition came to power.
The Home Secretary, Theresa May, remodelled the programme in 2011, following complaints that it was targeting the wrong areas and, in some cases, funding "extremist" causes.
But Ms Blears, a former Home Office minister who now sits on the Intelligence and Security Committee (ISC), said: "My disappointment is that the Government has retreated from this agenda. They find it easier to tackle far-right extremism. They have abandoned the field."
She said the Prevent element of the war on terror had become the "poor relation", compared with work pursuing suspects and preparing for terror attacks. The Government confirmed that 500 out of 2,500 young people identified as vulnerable to radicalisation have received support – including anger management and cognitive therapy.
Ms Blears said: "It is a bit trite to say we could have stopped this incident in Woolwich, but I do believe we all face a terrible threat from extremists. So it is essential we do everything we can to steer young people away from these pernicious individuals who are pulling them towards these extreme views."
The University of Greenwich confirmed that Michael Adebolajo, arrested following Drummer Rigby's death, studied there between 2003-2005, but he was not allowed to continue because "his academic progress was unsatisfactory". .
The vice-chancellor, David Maguire, announced an inquiry "into the association of these two individuals with the university, to assess whether there is any evidence of extremism in the university, past or present".