FORMER Labour Home Secretary Jack Straw has warned the Coalition that banning preachers of hate from television or the internet could act as a recruiting sergeant for extremists.

As armed police made the tenth arrest in connection with the murder of 25-year-old Army Drummer Lee Rigby in Woolwich, the former Cabinet minister urged caution, pointing to the unsuccessful attempts in the 1980s when Irish Republican leaders were deprived of the "oxygen of publicity".

Mr Straw stressed that while it was obvious bomb-making sites should be closed down and those who preach criminality should be banned, he advised ministers to be "very careful indeed about depriving people space to utter opinions the rest of us don't like".

He added: "One of the most intolerant and least successful measures that the Conservative government introduced was a decision by Douglas Hurd as Home Secretary to ban the IRA people from the airwaves. Actors had to do it.

"It was a great recruiting sergeant for them. The point about living in a democracy is you have to put up with people expressing views you really disagree with; it's important they are allowed to do that."

Mr Straw's remarks follow an indication from Theresa May, the current Home Secretary, that she is looking at extending the powers of Ofcom, the industry regulator, to enable it to intervene before certain broadcasts. At present, it can only intervene afterwards.

"One of the issues we need to look at," she explained, "is whether we've got the right processes, the right rules in place in relation to what is being beamed into people's homes."

The Home Secretary also questioned the BBC's decision to give airtime to Anjem Choudary, the former leader of banned Islamic group Al Muhajiroun, who spoke in the wake of Drummer Rigby's murder.

Yesterday, Tory MP Bob Stewart, a former colonel in the British Army, said Mr Choudary should be banned but stopped short of calling for a wider prohibition on extremists.

His Conservative colleague Mark Reckless was also critical of the BBC for giving Mr Choudary airtime but stressed a blanket ban on extremists should be a "last resort rather than the first response".

Shami Chakrabarti, director of the civil rights group Liberty, said care had to be taken about putting "political heat" on broadcasters.

"You criminalise speech when it crosses the line into inciting violence and murder. When it's just bad taste and extremist views, the future is about taking it on in heated debate," she said.

The solider's murder has provoked a backlash of anger across the country, with a large increase in anti-Muslim incidents including attacks on mosques, widespread racial abuse and comments on social media.

Two people were arrested after a fire was started at the Islamic Cultural Centre in Grimsby, although no-one was injured. Diler Gharib, mosque chairman, who was inside, said:"I grabbed a fire extinguisher and put it out and then two more petrol bombs hit the fire escape and the bin so I had to put those out too."

In London, The RAF Bomber Command Memorial monument and the Animals In War Memorial were daubed with the word "Islam".

Meanwhile, a 50-year-old man became the tenth to be arrested in connection with Mr Rigby's death. He was taken into police custody in south-east London on suspicion of conspiracy to commit murder.

In a separate development, more criticism was heaped on David Cameron for taking a holiday just three days after the tragedy in Woolwich. Rose Gentle, of Glasgow, whose son Gordon was killed by a roadside bomb in Iraq nine years ago, said the Prime Minister had made "absolutely the wrong decision" to go to Ibiza with his wife Samantha.