Theresa May warned today there are potentially thousands of people at risk of being radicalised in the UK as she indicated plans for a fresh crackdown on extremists groups.
The Home Secretary said around 500 police and security officers were working on the “horrific murder” of soldier Lee Rigby.
Mrs May said “all the indications” pointed to a lone wolf style incident rather than a wider planned operation.
Asked if she believed there were thousands at risk of radicalisation in the UK, she replied “potentially”.
Mrs May suggested a lower limit for imposing banning orders on extremist groups could be introduced.
She told the BBC’s Andrew Marr Show: “We do need to look at the powers, we do need to look at the laws.
“We do need to look, for example, at the question of whether perhaps we need to have banning orders to ban organisations that don’t meet the threshold for proscription.”
Tighter rules could also be imposed on internet service providers, the Home Secretary suggested.
She added: “One of the issues we need to look at is whether we have got the right processes, the right rules in place in relation to what is being beamed into people’s homes.”
Mrs May defended the “excellent” work of the security and intelligence agencies in the face of claims mistakes were made in the handling of the two suspects, identified as Michael Adebolajo, 28, and Michael Oluwatobi Adebowale, 22, who were known MI5.
A childhood friend of Adebolajo has also claimed that the suspect was approached by MI5 six months ago and asked if he would work for the security service.
Mrs May refused to be drawn on the details of the case but said said the security services worked in a “variety of ways”.
“They will approach individuals from time to time,” she added.
Detectives have made three further arrests in connection with the brutal killing. Two men, aged 24 and 28, were detained at an address in south-east London yesterday, while a 21-year-old man was arrested in the street in Charlton Lane, Greenwich, all on suspicion of conspiracy to commit murder.
Police from the Counter Terrorism Command, supported by specialist firearms officers, used Tasers to detain two of them, the 21 and 28-year-old. They did not need hospital treatment.