01:17

The attack outside the Houses of Parliament in London is the latest in a series of terrorist atrocities involving a vehicle being driven at speed into pedestrians – a tactic actively promoted by Islamic State.

In December, a man whose asylum claim had been rejected by Germany drove a truck into a market in Berlin, killing 12. Last July a stolen truck driven through a Bastille Day parade in Nice killed 86. The strikes appear inspired, if not actively commissioned, by Isis in Iraq and Syria.

In November a student used a vehicle and knives to injure 13 on a campus in Ohio, in the US. His motives and allegiance are less clear.

Such attacks are not unprecedented, but have become much more numerous in recent years.

In 2014 the chief spokesman of the group, Mohammed al-Adnani, issued a call for sympathisers in the west to strike “unbelievers”, especially police officers or soldiers, where they were – rather than travel to the middle east to fight there.

“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,” he said.

Though al-Adnani, who was killed in 2016, pointed a finger specifically at France, where there were two vehicle attacks in 2014, he also cited the UK among preferred targets.

• This section of the live blog was amended on 23 March 2017 to clarify a reference to the Berlin truck attacker.