We now know that the London Bridge terrorist, Usman Khan, was “a student and personal friend” of the Al Muhajiroun leader, Anjem Choudary. Following his conviction for terrorist offences, he served six years in prison. As Hannah Stuart, Head of Research at the Commission for Countering Extremism, noted in 2017, a high percentage of British terrorist convicts are connected to that group.

However, the ideological framework that supports takfiri jihadism is not limited to Al Muhajiroun.

Its essential components were spread over the course of the past 20 years, by an ecosystem of Islamist preachers who spoke at a series of British institutions. As a consequence, these preachers attained prominence and their theology increasingly became mainstream within a section of society. As we argue in our paper for the Commission for Countering Extremism, published in October 2019, those institutions which provided a base for this ideology could have been confronted and marginalised. That did not happen.

Instead they were treated as a valued part of British civil society. Hosting institutions received visits from politicians of all parties. They were praised by interfaith groups. Senior police officers spoke at their events. Civil society organisations, in particular those addressing the scourge of racism, treated them as partners.

It is instructive to consider the remarks of Lord Justice Leveson, who delivered the opinion of the Court of Appeal in Khan’s appeal against sentence:

This radicalisation was through the internet, inspired by the ideology and methodology of Anwar Al Awlaki (the now deceased Yemini based extremist) and the AQ magazine “Inspire” which he wrote, copies of which were found on computer equipment seized from the homes associated with many of the defendants. … A considerable body of extremist ideological material (with lectures by Anwar Al Awlaki) were found in the possession of the men when they were arrested.

Awlaki was the “leader of external operations” for Al Qaeda in the Arabian Peninsula, and was killed in a US drone attack on 30 September, 2011. He was also a leading figure in the network of Islamist preachers who toured Britain during the first decade of this century. His final appearance consisted of a video message at a conference entitled “The End of Time”, held at the East London Mosque’s London Muslim Centre, on 1 January 2009, where the other speakers were Uthman Lateef and Murtaza Khan, who shared key aspects of Awaki’s theology. He had previously appeared at a number of institutions in late 2003, including on the 26 December 2003, at an event organised by Islamic Forum Europe at the East London Mosque. At that event, he delivered a notorious speech, the conclusion of which was that Muslims should not “hand over” a “brother” to the police, even if they are accused of terrorism.

Along with other prominent jihadist theologians, Awlaki’s speeches and writings present a comprehensive ideological argument for jihad in support of a theocratic Islamic Caliphate. That argument can be summarised as follows:

The problems facing the world can only be solved by restoring the Caliphate.

The Caliphate will purify the world by implementing “the Sharia” and in particular, imposing capital and corporal “hudud” punishments.

Every Muslim has a religious obligation to work to establish such a Caliphate, including by supporting military jihad.

In our report, Mainstreaming Islamism, we provide examples from a wide range of speakers whose views conformed to these themes. A number of preachers and institutions also participated in and hosted events which presented those convicted of terrorist offences as heroes. Others engaged in incendiary rhetoric which disparaged friendships with non-Muslims, called for the stoning of adulterers, and the execution of homosexuals and apostates.

By promoting preachers with this reading of Islam as authoritative guides, their politics was normalised and propagated. It should be acknowledged that many preachers argued that a so-called “Covenant of Security” existed between Britain and Muslims, under which it would be improper to carry out acts of terrorism in this country. However, if an individual who had come to accept the the theological perspective advanced by such preachers came to believe that Britain had breached that Covenant – for example, by arresting those seeking to engage in military jihad abroad – they would naturally conclude that they were no longer bound by the prohibition against terrorism on the streets of the United Kingdom. At his trial in 2012, it emerged that this was the conclusion to which Usman Khan came.

The primary responsibility for spreading this ideology rests with the preachers, and with the institutions who provided them with platforms to spread their propaganda. However, we should not ignore the failure of politicians, police and civil society organisations to argue against and otherwise confront their activities.

Visits by public figures to institutions with a history of hosting problematic speakers, and joint ventures between such institutions and civil society organisations had the effect of strengthening their politics in two ways. First, engagement resulted in the collapse of the civil society cordon sanitaire, which hitherto had restricted these preachers to the fringes of public life. Secondly, uncritical engagement was employed to suggest that concerns about the nature of the speakers hosted by such institutions were misplaced, making it more difficult for Muslims who opposed the promotion of their politics to raise the alarm.

It is tempting to understand the 2019 London Bridge attack solely in terms of the malign influence of the Al Muhajiroun network. But the Islamist worldview is supported by a wider ecosystem of preachers, who share a common theological perspective, offering a range of opinions on when and where acts of violence may be carried out. This network could have been opposed and disrupted. Institutions aligned with this ideology should have been ostracised, instead of being praised and partnered with.

As a nation, we treated the problem in a cavalier manner. The folly of that error should now be apparent. Although some institutions no longer host the worst of the preachers we cover in our report, others still do. Their relationships with civil society continue. We are at risk of making the same mistakes all over again.