He says: “Prior to the terrorist lorry attack in Nice last July, where more than 80 people were killed and hundreds more seriously injured, firearms officers had the option of shooting at a moving vehicle but the national guidance discouraged that. It was felt shooting at a moving vehicle could increase the risk to the public.
“In light of vehicles being used as weapons by terrorists, the guidance was revised and it is now an accepted tactic that could be used in incidents such as those seen more recently in Sweden and Westminster.
“In addition, after the marauding firearms attack in Mumbai in 2008 we upgraded our weapons from 9mm carbines to the more powerful .556 carbines. These firearms are more effective against strong glass and body armour. They have been tested extensively and we know they can penetrate lorry cabs.
“Of course not every vehicle threat might be as a result of a deliberate terrorist act. For example, someone could be taken ill and lose control. Officers are trained to quickly assess situations such as this to try and determine whether a vehicle is out of control or being deliberately used to cause harm.
“Ultimately, as in any armed response situation, it would be for the officer to justify his or her actions but the fact that the threat has changed means they are now supported by the new guidance.”