Psychopaths are beneficial for society because in morally dubious situations they make pragmatic choices for the greater good, a new study suggests.

Although psychopaths are often viewed as dangerous, cold or lacking empathy, in fact, in certain situations, such traits can be helpful.

It means they would not think twice about shooting down an aircraft to prevent it from crashing into tower-block, or throwing a stranger under a bus to prevent it crashing into five people down the road.

A study led by the University of Plymouth, compared people’s judgements in moral dilemmas, to how they scored in measures of psychopathy. Around one in 100 people are thought to exhibit psychopathic traits.

In each dilemma, participants had to decide whether to sacrifice a person by performing a harmful action against them, in order to save a larger group of people.

In one moral quandary they were asked to push a victim off a footbridge into the path of an oncoming train to stop it hitting several workmen further down the track. In another scenario, they had to decide whether to stab to death an injured soldier to avoid him being tortured by enemy troops and giving away secrets which could jeopardise the platoon.