British universities are coming under the spotlight in the country's fight against terrorism, with critics calling them a hotbed of extremism while lecturers say any clampdown threatens their freedom of speech.
Prime Minister Gordon Brown recently highlighted universities as one of the key areas where authorities needed to act against extremist influences.However, a row is brewing over how officials can clamp down on radical groups recruiting students for militant causes without infringing on genuine academic debate.
The issue of campus extremism came to the fore in the aftermath of the London suicide bombings by four young British Islamists which left 52 people dead in 2005.
That was followed by a report by Professor Anthony Glees, director of Brunel University's Centre for Intelligence and Security Studies, which suggested campuses were a breeding ground for extremists.
Glees caused a stir across the academic community by estimating that dozens of British universities had been infiltrated by fundamentalists, based on historical terrorism cases which had involved students or former students.
He now says the situation is even worse.
"What we have seen since 2005 has been an increase in the number of students and former students involved in terrorist crimes," he said.
"And we are even more entitled today to speak about there being a significant number being involved in Islamist terrorism. The evidence is even stronger and more compelling today than it was in 2005."
In the immediate aftermath of the September 11, 2001 attacks on the United States, British security services estimated there were a few hundred potential Islamist militants in the country.
Now they say they are tracking around 2,000 suspects spread between some 200 networks, while the growing number of plots police say they have foiled indicates the country is at the centre of Islamist activities in the West.
Glees believes that universities provide the perfect cover for radicals to recruit and groom passionate young men.
Two of the London suicide bombers had studied at Leeds Metropolitan University.
In September, a Scottish student was jailed for distributing terrorist material via web sites.
Earlier this year, four students from Bradford University were jailed for possessing articles for terrorist purposes.
Detectives said they suspected the men intended to go and fight coalition forces in Afghanistan.
"The problem stems from the fact that extremists and extremist recruiters have seen universities as safe spaces from which to recruit students," Glees said.
"The universities are not properly supervising what goes on at campuses, they weren't and they're still not, and it is clear they don't intend to do so in the future."
The government acknowledges there is an issue but says it is not as bad as Glees suggests.
"We do not agree with Professor Glees' assessment of the extent of al Qaeda-inspired violent extremism in our universities," Bill Rammell, the minister for higher education, said via email.
"The evidence tells us that there is a serious but not widespread problem."
But although ministers say universities are not the hotbeds of activity as Glees suggests, they have called for academics to do more to help monitor extremism or incitement on campuses.
That has met with anger and fierce opposition from lecturers who say it is an attack on their freedom, and that academics and students must be allowed to discuss ideas even if they are considered offensive or extreme.
In May, the University and College Union (UCU) passed a motion rejecting the government's call which amounted to increased surveillance of Muslim or other minority students and to the use of members of staff for such witch-hunts".
"Lecturers want to teach students, if they wanted to police them they would have joined the force," said UCU General Secretary, Sally Hunt.
"The last thing we need is people too frightened to discuss an issue because they fear some quasi-secret service will turn them in."
Students are equally dismissive of suggestions universities had been infiltrated by militants.
"This is simply untrue and no evidence has been put forward to substantiate these very serious allegations," said Faisal Hanjra, a spokesman for the Federation of Student Islamic Societies which represents 90,000 students.
"The accusations put forward by the likes of Professor Glees have been dismissed by all those working in the higher education sector."
Even Dr John Hood, Vice-Chancellor of Oxford University, has stepped into the row, arguing that exposing young people to powerful ideas was part of the educational process.
"There has already been talk, not all of it well thought through it seems to me, about the `policing' of campuses," he wrote recently.
In the next few weeks, the government will meet with university chiefs to discuss "how we maintain academic freedom whilst ensuring that extremists can never stifle debate or impose their views."
"We are not asking and have never asked universities to spy on or monitor extremism," Rammell said.
"The guidance we issued to vice chancellors last year and are in the process of updating gives advice on how to ensure ... tolerance and open debate, protect vulnerable students, protect staff and students and tackle violent extremism where it may appear."
Glees is adamant that the softly-softly approach will not work. He said students should learn about radical ideas but the real issue is who teaches them and where.
"The people who are going around on campuses aren't learned professors and bright young dons - they are the same sort of people who go round radicalising people in prisons, madrassas and mosques," he said.
He cited a number of former Islamists such as Ed Hussain who wrote a book about his experiences in which he documents radicalisation at universities.
"It is mischievous nonsense to claim that the government or I advocate that academics should spy on students. All academics should do is their very best in exercising the duty of care that they have to students."