Thousands living in Britain may be on the path to 'violent extremism', Home Secretary warns Theresa May says 500 police investigating murder of Lee Rigby in Woolwich She maintains 'all the indications' are execution was a lone wolf attack Reveals 2,000 potential radicals spoken to by Government in past year Home Secretary launches bid to force through 'essential' snooper's charter Slams BBC for inviting Choudary onto Newsnight to give 'disgusting' views Warning: Theresa May said today that 'potentially' thousands in Britain could be on the path to violent extremism Thousands of people living in Britain could be 'on the path' to becoming violent radicals and terrorists, the Home Secretary said today. Theresa May gave the warning as she confirmed a fresh crackdown on extremist groups who could be a threat to national security. The senior Tory also used an interview on the BBC's Andrew Marr Show to criticise the Corporation for interviewing radical cleric Anjem Choudary. He was given star billing on a discussion panel with Newsnight presenter Kirsty Wark, as he insisted he was not a "hate preacher" or Islamic extremist. Mrs May said: 'I think Anjem Choudary has disgusting views and I think it is right that we look at how those views are being presented and I think there were many people who did indeed say "What is the BBC doing interviewing Anjem Choudary?" After his appearance two days ago, the BBC was branded 'idiotic' and 'insensitive'. Around 500 police and security officers are working on the 'horrific murder' of soldier Lee Rigby, Mrs May also revealed. But despite more arrests linked to the killing overnight, she 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'. 'We have people at different points on what could be the path to violent extremism,' she said. She added that the Government 'Prevent' scheme designed to reduce radicalism in Britain had spoken to 2,000 people at risk in the past year, particularly in prison. Mrs May also 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 Adebowale, 22, who were known MI5. Criticised: Anjem Choudary was asked onto Newsnight this week, where he was interviewed by Kirsty Wark, a decision which has been widely panned 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 said. 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. Mrs May also insisted the failed 'snooper's charter' would be revived as she appeared to be gearing up for a fight with Liberal Democrats. Earlier this month Deputy Prime Minister Nick Clegg blocked the Home Secretary's plans for a communications bill that would have given police and security services access to records of individuals' internet use. Row: Former Home Secretary Alan Johnson said that Theresa May should resign if she cannot push through laws that allow the authorities to snoop on what people look at online Labour former Home Secretary Alan Johnson said today he was 'absolutely passionately' a supporter of reforms and suggested it was a resigning issue for Theresa May if she could not get the changes into law by 2015. Asked whether she would quit over the matter, Mrs May told the BBC's Andrew Marr Show: 'I have made my view very clear. We are now working through across the government what action we can take but I'm clear, the law enforcement agencies, the intelligence agencies need access to communications data and that is essential to them doing their job.' The Home Secretary said there was a reference to the plans in the Queen's Speech. She added: 'I have always been clear that access to communications data is essential for law enforcement agencies and the intelligence agencies. There is a reducing capability in relation to access to communications data.