The use of vehicles to carry out terror atrocities across Europe has forced the security services to rethink their counter-terrorism strategy.
Stockholm, where a radicalised, determined killer used a truck to bring carnage to the city streets, has grimly highlighted how difficult it is to defend against low-tech terror.
What will have particularly worried Western security officials was that Rakhmat Akilov, 39, an asylum seeker from Uzbekistan, had also managed to turn his vehicle into a moving bomb.
Had the home-made explosive device detonated, the death toll would have been much higher.
Security chiefs have long feared a shift from sophisticated terror plots, popular with al Qaeda, to attacks carried out by lone wolves making use of weapons from whatever is at hand.
It means the often slow build up to an attack, which has proved vital in providing intelligence warnings of such plots, is no longer available.
The Stockholm attack took place less than a fortnight after a similar atrocity carried out by Khalid Masood, who drove a car into pedestrians on Westminster Bridge and then stabbed to death a policeman at the Houses of Parliament.
And on the day after the Westminster attack, Belgian security agencies responded to what they described as a possible terror incident after a man drove a car towards pedestrians in the Belgian capital Antwerp.
These attacks have placed front-line counter-terrorism units across Europe on high alert.
But the warning signs indicating a switch to low-tech terror were clear more than two years ago.
Low-tech terrorism is now the terrorism of choice for Islamic State and can be traced back to the speeches of IS-chief strategist Abu Muhammad al-Adnani, who was killed in an air strike last year.
Adnani, a Syrian national. was believed to be the mastermind behind the sophisticated murderous bomb and gun attacks on Paris in 2015 and Brussels in 2016.
But even before Paris and Belgium, Adnani had released a speech in which he called on Muslims in the West to target civilians and military personnel in their own countries.
It was a tacit acknowledgement that the future of Islamist terrorism lay in the moblisation of low-tech terrorists. Adnani urged Muslims to kill “in any manner or way however it may be.”
In a piece of chilling rhetoric Adnani detailed how his orders should be carried out: “If you are not able to find a bomb or a bullet, then smash his head with a rock, or slaughter him with a knife, or run him over with your car, or throw him down from a high place, or choke him, or poison him … If you are unable to do so, then burn his home, car, or business. Or destroy his crops. If you are unable to do so, then spit in his face.”
French citizens were the first of a wave of extremists to take up Adnani’s call to carry out low-tech terrorism.
In Dijon, the central French city, in December 2014, and in Nantes, in western France, a day later – there were incidents where cars were used to drive at pedestrians.
Adnani’s call is believed to have triggered an attack in Quebec in 2015 in which a man rammed his car into two Canadian soldiers, killing one of them.
But the most serious terror atrocities adapting vehicles as weapons were the truck attacks in Nice and Berlin last year. Eighty-four people died in Nice and 12 people were murdered in Berlin.
Security chiefs have long warned that the Islamist terrorist threat facing Europe has never been so great. But now they know that the low-tech nature of the attacks can make it impossible to stop.
- Robert Verkaik is the author of Jihadi John: The Making of a Terrorist
- He tweets at @robertverkaik1
