Thus is why our police officers don't have guns (except for the ARUs). It's also why we have such strict controls on all weapons.

The mix of adrenalin, institutional racism and firearms is a volatile one.

But there is also a difference of culture. In the USA, the police are a paramilitary organisation welded together from security guards employed to protect property in the cities, sheriffs and deputies in near-lawless frontier towns and gangs raised to hunt down fleeing slaves. They are supposed to enforce the law amid an armed citizenry. They are conditioned to expect armed resistance and respond with maximum force.

The traditional roles of the Parish Constables who were the origin for the British police were to ensure that those summoned to Court duly appeared, and to "maintain the Kings' (or Queens') peace". When Sir Robert Peel first formed the Metropolitan Police, it was on the same basis, with the added responsibility of apprehending those caught in criminal acts. They were equipped with a truncheon, a lamp and a whistle or rattle. Because Peel wanted them to be used instead of the military to maintain public order, he went out of his way to ensure that their uniform and ranks bore no resemblance to those of soldiers - hence ranks such as Inspector, Superintendent etc.

British law also has key differences. One is the concept of 'reasonable force', which allows a jury to decide if the response to an actual or implied assault is proportionate to the perceived threat. On the whole, this leads to a policy of minimum force on the part of the police, though civilians have occasionally overdone things.

Second, there is the legal concept of 'duty of care'. This is "the legal obligation or responsibility to take all reasonable steps to avoid causing foreseeable harm to another person or their property." It applies to all organisations and indeed individuals. In the UK, those police officers would have known they had a duty of care to Ms Massey. If she was obviously distressed, they would have been trained to either call in a woman officer or paramedic.

This doesn't stop bad things happeing over here, but they are usually non-lethal and far less depressingly commonplace.