Others will bring expertise to bear on the wars in Afghanistan and Iraq, Al Qaeda, the extension of Iran’s influence, ISIS, neo-conservatism, Boko Haram, the trend in the U.S and the UK first to liberal intervention and then to military withdrawal, al-Shabaab, the ambiguous role of Saudi Arabia, Jamaat Nasr al-Islam wal Muslimin – and much else that has happened in the 20 years since 9/11.

I’ve had no exposure to Islamist extremism abroad, but have a long interest in its presence in Britain – having served as MP for what was then the Conservative seat with the highest number of Muslim constituents, Wycombe, for the best part of ten years.

Terror came to the UK four years later, on 7/7, claiming 52 lives and more than 700 injuries.  Extremism had been with us for longer – having first come to public attention during the death threats and book burnings of the Satanic Verses affair.  Has government got better or worse in response to both?  Is the challenge that they pose more or less serious?

You must make your own judgement on domestic terrorism, and the horrors that followed 7/7: the murder of Lee Rigby, the Manchester Arena bombings, the London Bridge attacks, and more.

The record can be viewed either as evidence of lamentable failures by the security services, or of their relative success, in that there have not been even more fatalities and injuries.  Given the steady trickle of British Muslims abroad to fight in Syria, say – and the return of some of them to Britain – that there has not been an upward trend in terror incidents is striking, perhaps surprising, and suggestive.

The state’s reaction to terrorism should be simple (though it isn’t easy): preventing attacks and punishing criminals.  Responding to extremism is less straightforward.

For a start, there’s been debate in the public square, for the best part of the 20 years since 9/11, about whether there’s a connection between extremism and terror at all: in the wake of the Iraq War, some held that is mainly driven by western foreign policy and the invasion of Muslim-majority countries.

This divided both the main political parties.  On the one side, broadly speaking, was Tony Blair and Michael Gove; on the other, Sayeeda Warsi and Jeremy Corbyn.

We would argue that the Charlie Hebdo murders in Paris, say, or the bombings of Sufi shrines in Pakistan, show that while western foreign policy can soothe or inflame the problem, its main cause is a global struggle within Islam itself over its future.  Labour held that position under Blair.  The Conservatives kept it going under David Cameron, Theresa May and now Boris Johnson.

Whatever your take, government is much better informed about Islam and Islamism in Britain than it was 20 years ago – when, despite the radicalisation of many British Muslims during the 1990s over Bosnia, it knew, frankly, almost nothing at all about it.

Again, you must make up your own mind on whether Islamist extremism is stronger or weaker among British Muslims than it was on 9/11.  The picture painted by Ed Husain in  hisAmong the Mosques is bleak, though he also writes that “there is a new Western Islam progressing here; it is just that the people who are developing it are shouting less loudly than the caliphists.”

Which leads me to make the only other point I’ve room for in a piece of a thousand words: namely, that attempts by both Labour and Conservative governments to encourage those Muslims to shout just as loudly have failed.

I’ve seen two kinds of attempts made over the last 20 years, one political, the other religious.  The political attempt was the Quilliam Foundation, in which Husain himself was originally involved.  It shouted very loudly indeed – its main message being that British Muslims have a responsibility to do the same and weren’t acting on it.

Failure is a relative term, in the Quilliam context anyway.  My judgement is that the noise it made, against a background of other challenges to Islamist ideology by some politicians, academics and others, did influence the national conversation, both outside Britain’s Muslim communities and to some extent within it.

But there has been no successor body; no mass movement.  Nothing followed in Quilliam’s footsteps. The religious movements have been even less successful.  Consider the failure of the Sufi Muslim Council.

The reason isn’t hard to grasp.  There are a mass of devout British Muslims who reject not only terror but extremism – by which we mean, in the absence of a better definition, the belief that people should be treated on the basis of religion rather than on that of citizenship.  With Muslims at least, if not others, governed by an Islamic state implementing a pre-modern form of sharia.

However, the hard lesson of the past 20 years is that while these Muslims aren’t politically extreme, they can be religiously so: consider the Satanic Verses-type rows since, from the eruptions over the Danish cartoons to the Bradford teacher who has been forced from his job.

The reaction to the murder of Salman Taseer in 2011 – then the governor of Punjab province, who was critical towards Pakistan’s blasphemy laws – by some in the Barelwi movement was a watershed moment.  They hailed his killer, Mumtaz Qadri, as a martyr.  The Barelwis have a substantial presence in the UK, and are certainly not an Islamist movement.

However, politicians who hoped to see such groups organise themselves to challenge Islamist extremism have, as the Qadri case suggests, found themselves caught up in inter-Muslim rivalries that are not so much political as religious.

None of this is to say that British Muslims don’t react against extremism.  Many do, as Husain points out – but, rather than confront it directly, they opt simply to get on with their lives.  Others do work, organise and mobilise, within mosques and outside them.  But they tend to be active in their local communities rather than on a national scale.

British politicians are now tempted to view 9/11, and the asymetic struggle that followed, as an exception rather than the rule: 20 years in which China had not yet emerged as a Westminster preoccupation, and Russia as a threat to our common European security.

I suspect that the worldwide struggle within Islam will have further impacts here.  And that many non-Muslims will continue to conflate Islam, an ancient religion, and Islamism, the modern ideology.  Which will mean yet more anti-Muslim prejudice and hatred.  The return of Taliban is a reminder that Islamist extremism is alive and well.