It is self-evidently true that the West has never been more at risk from terrorism than when it went to bed on 10 September 2001.

A company called Google was two years old. Facebook was years off invention, likewise YouTube. The iPhone would not be released for another six years, and as such no one had yet dreamt up WhatsApp.

More to the point, those “foreign wars” that breed extremism, at least according to Jeremy Corbyn and the more than 50 per cent of the population who apparently agree with him, in Afghanistan, in Iraq and in Libya, had not yet been fought.

But action was taken: stricter security at airports, pilots locking themselves in to the cockpit on planes (a policy that was itself the prime factor in an act of mass murder by a Germanwings pilot).

London terror attack: Everything we know so far

And the targeted capture or assassination, by a broad coalition of western powers, of the leaders of the group that had perpetrated the attack, al-Qaeda, in the country that had happily hosted them, Afghanistan.

Sixteen years later, even in the wake of two deadly attacks on British streets in two weeks, it is hard to argue that the world, certainly the Western world, is not a safer place than it was then.

In response to such atrocities, there will always need to be a call to action. This time, it is the internet and the big tech companies who must carry the can for these outrages.

“We cannot go on as we are. Enough is enough,” Theresa May said in a speech on Sunday morning. She would, she said, be “working with other democratic governments to agree ways to regulate cyberspace and prevent the spread of extremism and terrorist planning online.”

But the Prime Minister knows as well as anyone that, for example, international agreements to stop Isis posting its propaganda videos on YouTube will make virtually no difference. The fight she and the rest of us must win is against the ideology itself.

London Bridge Terror Attack Show all 16 1 /16 London Bridge Terror Attack London Bridge Terror Attack Armed police on Borough High Street as police are dealing with a "major incident" at London Bridge PA London Bridge Terror Attack Armed Police talk to members of the public outside London Bridge Hospital as police are dealing with a "major incident" at London Bridge PA London Bridge Terror Attack Police Officers outside the Barrowboy and Banker Public House on Borough High Street as police are dealing with a "major incident" at London Bridge PA London Bridge Terror Attack Armed Police talk to members of the public outside London Bridge Hospital as police are dealing with a "major incident" at London Bridge PA London Bridge Terror Attack Armed police on Borough High Street as police deal with a 'major incident' at London Bridge PA London Bridge Terror Attack Emergency services near the scene of the incident Screengrab London Bridge Terror Attack People run down Borough High Street as police are dealing with a "major incident" at London Bridge Reuters London Bridge Terror Attack Emergency services arrive at the scene near Borough market at London Bridge Carl Court/Getty Images London Bridge Terror Attack Emergency personnel on London Bridge as police are dealing with a "major incident" at London Bridge PA London Bridge Terror Attack Police sniffer dogs on London Bridge as police are dealing with a "major incident" at London Bridge PA London Bridge Terror Attack A second helicopter lands on London Bridge as police are responding to three incidents in the capital, amid reports that a vehicle collided with pedestrians on London Bridge, Scotland Yard said. Officers are dealing with reports of stabbings in Borough Market, where armed officers attended and shots were fired. They are also at an incident in the Vauxhall area PA London Bridge Terror Attack Police attend to an incident on London Bridge in London REUTERS London Bridge Terror Attack Police attend to an incident on London Bridge in London, Britain Reuters London Bridge Terror Attack A police officer escorts members of the public to safety at London Bridge Getty Images London Bridge Terror Attack Police attend to an incident on London Bridge in London, Britain Reuters London Bridge Terror Attack Police attend to an incident near London Bridge in London, Britain Reuters

She said as much herself: “We must do more – much more – to take on and defeat the evil ideology of Islamist extremism that preaches hatred, sows division, and promotes sectarianism. It is an ideology that promotes a false choice between our Western values of freedom, democracy and human rights and the religion of Islam. It is a perversion of Islam and a perversion of the truth.”

This is a far more complex challenge. Shutting down YouTube or cracking open WhatsApp does not kill off an idea, an idea that was arguably best expressed by Barack Obama in an interview with Vice News two years ago. He spoke specifically about Yemeni youth, but it is hard not to imagine such sentiment applying to the appalling people who did what they did in London and Manchester in the last two weeks.

“I’m worried about how, even if ISIL is defeated, the underlying problem of disaffected Sunnis around the world ... where a young man who’s growing up has no education, has no prospects for the future, is looking around and the one way he can get validation, power, respect is if he’s a fighter. ‘This looks like the toughest gang around, so let me affiliate with them, and now you’re giving me a religious rationale for doing this.’ That’s a problem we’re going to have, generally.”