Tories were accused of "giving in to terrorists" and risking radicalising more young people by seeking a ban on extremist preachers from university campuses in a coalition row over how to respond to Islamic State.

New laws place a duty on institutions to prevent students being drawn into terrorism but the governing parties are split over how it should be implemented in official guidance to educational leaders.

Attention has been focused on efforts to prevent young people being lured into joining terror groups by the unmasking of the Islamic State (IS) executioner known as "Jihadi John" as British computer graduate Mohammed Emwazi.

Labour demanded a watchdog investigation into whether a relaxation of the "control order" system for keeping suspects under surveillance had allowed Emwazi and others to slip through the net and join Islamist fighters in Syria and Iraq.

But politicians on all sides continued to defend the work of the intelligence services against suggestions MI5 contacts with Emwazi could have contributed to his radicalisation as emails emerged in which he said he feared he was a "dead man walking".

Conservative Party chairman Grant Shapps confirmed there was a "difference of opinion" over the guidance to be issued to universities but said his party was determined to ensure the public was protected.

"Vince Cable doesn't want to do what the Conservatives want to do which is to make sure that on campus we do not have radical preachers saying things which incite violence which ultimately can lead to the radicalisation of young people," he told Sky News Murnaghan programme.

The Lib Dem Business Secretary's department deals with higher education.

"We have seen these three girls go off to Syria. We have seen Jihadi John. We don't think that sort of preaching should happen in our universities.

"People in Vince Cable's constituency of Twickenham or around the country deserve that protection and that means that we have to put proper, decent, tough rules in place which don't ban free speech but do prevent people from preaching death."

But Lib Dem Energy Secretary Ed Davey said it was anti-free speech for the state to try to define what was "extremist" and would simply drive unpalatable views underground.

Drawing a parallel with previous calls to ban the far-right British National Party from campuses, he said: "Racist views are abhorrent and they are very easy to demolish. Equally, some of the appalling views of some of these preachers are easy to demolish.

"If these preachers are inciting violence, if they are saying it is OK to be a terrorist, if they are saying you can cut off people's heads, they can and should be arrested and Liberal Democrats are clear that that law should hit them with full force.

"What the Conservatives seem to be wanting to do is to introduce - against British values of free speech - a new type of rule that says that the state will know what 'extremism' is.

"The phrase 'extremism' they are talking about is very, very nebulous, it is unclear, and there is a danger that the Conservatives will clamp down on free speech and that will be giving in to the terrorists. We are not prepared to do that."

He added: "What the Tories are asking for would make radicalisation worse ... because it would push these people into a more secret world which we know exists and therefore they couldn't be challenged.

"The beauty of democracy, the beauty of free speech is that it stops these appalling views taking root."

In a 2010 email exchange with Mail on Sunday security editor Robert Verkaikat, Emwazi said he considered suicide after coming face to face with what he suspected to be a British intelligence official as he attempted to sell a laptop computer.

He said he felt harassed by security services, in a series of emails in 2010, three years before he left to join IS, saying: "Sometimes I feel like a dead man walking, not fearing they (MI5) may kill me.

"Rather, fearing that one day, I'll take as many pills as I can so that I will sleep for ever! I just want to get away from these people!"

Kuwait-born Londoner Emwazi had been pinpointed as a potential terrorist by the British authorities but was nonetheless able to travel to Syria in 2013 and join a group responsible for the murder of several Western hostages.

Former independent reviewer of government anti-terror laws Lord Carlile said there was a "realistic prospect Emwazi might have been prevented from joining up with IS had restrictions on suspects not been relaxed.

Shadow home secretary Yvette Cooper claimed the security services' hands were tied for nearly five years by Mrs May's "wrong" decision to scrap powers to move terror suspects away from their networks.

Relocation powers have been reintroduced by the coalition this year but Ms Cooper called for the security services to immediately brief the Intelligence and Security Committee on how the loss of the measures might have affected their work.

"The fact that Theresa May could take the decision to remove those relocation powers against all that expert advice, against the arguments that were made in Parliament, I think was the wrong thing to do," she told BBC1's Andrew Marr Show.

"We do need to know more about whether that has increased the risk as a result, about what difference it's made to some of these very serious cases.

"I think the Intelligence and Security Committee needs to be briefed immediately on the details of these cases and whether or not it could have been handled better if they had been able to be moved outside London."

Scotland Yard's senior counter-terrorism officer Helen Ball said relocation powers are a valuable tool to move people away from networks that might be fuelling and encouraging extremism.

The deputy assistant commissioner told the programme: "That element we have always felt was useful. We have also always said though that short of locking someone up for 24 hours a day you can't eliminate the risk that they pose."

On BBC Radio 5 Live's Pienaar's Politics, Mr Shapps and Mr Davey struggled clearly to specify what types of extremist speech were under dispute.

"You're asking for an absolute line and the truth of the matter is what constitutes stepping over that line is something which is forever in any case interpreted by the law and in courts," Mr Shapps said.

"What we're saying is that if we believe somebody comes into university and they preach extreme hate, if they preach that students should effectively be radicalised, then that is going too far.

"We don't have a problem - at all - with free speech with people talking about different belief sets and what motivates and drives people.

"But ... we err on the side of caution because we think that protects the British public. The Liberal Democrats have a more liberal view."

Mr Davey told the programme: "Well as I understand it, they are saying that if people who have Islamic views - who are saying that they should have a caliphate - then that is wrong."