1) The most effective protectors against extremism are a commitment to the values of a free society and the spirit of 'live and let live' that are hallmarks of British society. Conversely, any lack of confidence in, or undermining of, these values will weaken that protection.
2) Those individuals and families who leave this country to go to Syria/Iraq to fight or who plan/undertake acts of terror in this country have made a conscious decision to cross the line taking them not only physically out of Britain but also to cut ties with family, friends and colleagues which normally bind people together in community. The influences on this break are therefore central to understanding 'Islamist' extremism.
It is evident from 'martyrdom videos' and statements like that of the Luton Mannan family that a) they identify only with fellow Muslims' suffering b) often make reference to Islam's great and glorious past (compared to its perceived degenerated state now), c) make reference to the West's corruption, and sometimes to the need for liberation from man-made laws. While a number of terrorists have been linked in some way to al Muhajiroun, there are numerous internet sites and chatrooms which promote grievances and victimhood, or discus how far a believer can or cannot integrate into Western society.
Nearly all of the terrorists who have left testimony can be said to ascribe to the Myth of Unique Muslim Victimhood-i.e. that only Muslims are victims and only Muslims can be victims. The truth is that around the world Muslims, Christians, Jews, Hindus and atheists etc are victims of horrible persecution and that people from all of these backgrounds can be perpetrators. This understanding, empathy with victims universally and that one's own co-religionists can be guilty, is entirely missing in violent extremists' expressed world view. Crucially, these themes also encompass the beliefs and actions of 'hate preachers' and of the organised theocratic parties such as Hizb ut Tahrir, the Muslim Brotherhood, Jiamat i Islami and their various 'front organisations.'
3) Grievances regarding the clear suffering of Muslims' around the world are woven into a meme that there is a conspiracy against Islam. But in this country the main target outside of the Iraq issue, of more force given the passing of time since the invasion, and its perennial importance is Israel and the Palestinians. This is especially significant given the cross-party support for a two state solution, but also the identification of Palestine by the Stop the War Coalition, many left-wing groups and by organisations such as the NUS as a cause in which to take sides-rather than as a nuanced issue which requires some perspective and distancing from impassioned involvement.
It is necessary to offer context and perspective on the Palestine situation. For example, the actions of Amin al Husseini in organising terrorist attacks on Jews even before the Holocaust (which he aided by propaganda, using his influence to block Jewish refugees' leaving Axis-controlled territory and the raising of SS troops in the Balkans) or of the establishment of the state of Israel. Moreover, it is a little remembered fact that the Mufti also had many of his political opponents assassinated-including those who wished to live side by side with Jews in peace. A particularly significant event, which has resonance today both in Jerusalem and this country, is his action of sending agents with faked photos of the al Aqsa mosque burning which provoked the 1929 Hebron massacre and has poisoned Jewish/Palestinian relations to this day. The cry of 'al Aqsa in danger' not only leads to violence in Jerusalem but the Friends of Al Aqsa in this country, fronted by Ismail Patel, promotes the same theme in the UK and therefore contributes a specific toxic issue to a general sense of grievance.
4) PREVENT and CST are subject to particular opposition from the Islamist parties and their front organisations (for example the Cordoba Foundation-a front organisation of the Muslim Brotherhood), but also various 'advocacy' groups such as MEND, Cage and Friends of al Aqsa. The NUS and various trade unions have also passed resolutions condemning PREVENT and charging the UK government with endangering independent academic enquiry and free expression, demonising Muslims and turning lecturers into terrorism prevention officers. The 'advocacy' groups actually promote a sectarian and supremacist view. In the case of Friends of al Aqsa its work generally and on campus is likely to have a particularly incendiary effect. FOA and Cage have even participated in mainstream academic conferences, notably the recent 'Understanding Conflict: Research, ideas and responses to security threats' event at Bath University. 
The opposition of the NUS and UCU and concerns expressed by some vice-chancellors exposes a set of double standards. All of these organisations have anti-racism & fascism policies pledging to tackle racism and fascism, to identify and expel lecturers identified as racist and to confront racism in all its forms.If any group or individual were to appear on campus ranging from the BNP to the obscure White supremacist National Action, they would be readily identified and opposition raised through official channels and Hope Not Hate and Searchlight. Yet the claim is made both that Islamist extremists cannot be identified and that to refuse them the opportunity to speak and organise would threaten democratic principles. Moreover, both the NUS and UCU have a 'no platform' policy which logically should be extended to clerical fascists.
In 2005 Universities UK published 'Promoting good campus relations: dealing with hate crimes & intolerance.' The steering group included reps. from UNISON, NUS, SCOPE, NATFHE, HEEON and was chaired by Prof. Les Ebdon, the vice-chancellor of the University of Luton.  It stresses the duty to promote good relations on campus, includes the ability to take pre-emptive action and includes a helpful flow-chart indicating possible interventions for those responsible. Thus, there should be little difficulty in including Islamist groups, although it may take more research effort on these groups from university and student union authorities. The danger from these groups and speakers arises from their grievance mongering, always focusing on Muslim suffering, and narrowing of the options for action by 'faithful believers.'
5) The CST requirements regarding speakers on campus would not ever have been proposed if there was robust challenge to sectarian and clerical fascist ideas on campus. But no such challenge exists. Indeed, ironically, the most recent egregious attacks on free speech have been aimed at atheist Leftists and feminists. Freedom of expression is central to British values and rests fundamentally on the idea that “If liberty means anything at all, it means the right to tell people what they do not want to hear” (Orwell). There is a frequent confusion and conflation of the terms toleration and respect, but they are not the same thing. In a free society we are obliged to tolerate views with which we fundamentally disagree. Moreover, there is no right to respect or not to be offended. Attempts to establish 'triggers' and 'safe spaces' are inimical to the spirit of the university and to a free and open society.
These errors are compounded by the extension of Left-wing opposition to 'racist & fascist speakers to include so-called Islamophobic 'New Atheists,' supporters of Israel and even feminists. In addition there is an alliance, whether principled or opportunist, between some sections of the Left and Islamists.  Thus, the broad-based opposition to Neo-fascist and White supremacist extremists does not exist in relation to Islamism. This, and the lack of objection to 'voluntary' gender segregation, has removed a large section of the spontaneous safety barrier to extremism and has provoked intervention by central government. 'Extremist speakers' are not challenged on campus and it is no good pretending that they are. The extension of 'Islamophobia,' which is a fiercely contested term, to physical attacks on Muslims is additionally unhelpful.
Conclusion: The non-violent extremist threat essentially comes from the promotion of sectarian identity. Those individuals and groups who promote a narrative of grievance connected to a restricted definition of what constitutes a faithful believer are dangerous. Those which particularly emphasis incendiary issues such the 'Al Aqsa in danger' message are particularly so. These messages are communicated in a number of media, but particularly on the internet and on campus. A common sense of humanity is an antidote to narrow sectarian identification, coupled with commitment to the fearless expression of our right to free expression and the feeling of 'neighbourliness.' Relentless public opposition to the Islamist parties, their front organisations and the pseudo advocacy groups is essential. This requires support for censored speakers. But in the absence of what has previously been a wide and inclusive opposition to all extremism, the government's proposed targeting of so-called hate preachers lacks a credible alternative.
 eg Mohammed Siddique & the Tel Aviv suicide bombers
 'We release this statement to confirm that, indeed we are in the Islamic State. A land that is free from the corruption and oppression of manmade law and is governed by the shariah, the perfect and just laws of Allah. All 12 of us and why should this number be shocking, when there are thousands and thousands of Muslims from all corners of the world that are crossing over land and sea everyday to come to the Islamic State? That are willingly leaving the so called freedom and democracy that was forced down our throat in the attempt to brainwash Muslims to forget about their powerful and glorious past and now present.' http://www.dailymail.co.uk/news/article-3149190/All-12-Islamic-State-Luton-family-release-statement-confirming-Syria.html
 e.g. http://www.ummah.com/forum/archive/index.php/t-171474.html
 see http://www.foa.org.uk/ 'Hands Off al Aqsa' and associated inflammatory articles
 UCU statement http://www.ucu.org.uk/index.cfm?articleid=4546
 From the Latin 'to endure'-as in to endure pain
 See the International Socialist website for a justification for this seemingly odd alliance based on an ostensible re-reading of Marx (or do hitherto marginalised Left groups see a revolutionary oppressed class of people who can be mobilised?) http://isj.org.uk/more-than-opium-marxism-and-religion/