Nota: uno studio inglese potrebbe spiegare il comportamento del prefetto di Trieste.

Psychologists  have  struggled  for  decades  to  explain why ordinary people  participate  in  atrocities such as the Nazi Holocaust or the Stalinist purges.

Now  experiments carried out in Britain reveal that most people obey authority unquestioningly and would also walk past an injured stranger who did not come from their own ethnic or social group.

The findings will shake the long-held British belief that this country is immune from the kinds of tyranny found in other parts of the world.

Research carried out at Lancaster University on football supporters found  that  they failed consistently to come to the aid of an injured supporter from a rival  team. Secret  cameras  filmed  individual Manchester  United  fans as they ignored a Liverpool fan played by an actor while he writhed in pain on the floor. When the actor wore a Manchester  United  shirt, the supporters helped him in 80 per cent of cases. When he switched to a Liverpool shirt, all but a handful walked straight  past. The results of the research will be revealed in a BBC programme,  Five Steps to Tyranny ,  on the nature of evil to be presented by Sheena McDonald this week.

A  separate  experiment - again filmed with secret cameras - shows the majority of  people  on  a train complying with a stranger's order to give up their  seat.  When the stranger is accompanied by a man in a uniform, not a single person chooses to disobey.

McDonald said she was shocked by what the experiments showed: 'The majority of people have a psychological tendency to obey and conform. All of us involved in the programme found ourselves looking at our own lives and examining whether we were beginning on the first step to tyranny.'

Dr  Mark  Levine,  the psychologist who developed the football fan experiment,  said:  'These  are  ordinary people.  If you ask people whether they would help a stranger in distress, they say they would. But  in reality they just don't do it. When we asked people afterwards why  they didn't intervene, they said they didn't consider the pain as serious when they saw the person was wearing a Liverpool shirt.'

Colonel Bob Stewart, former commander of UN forces in Bosnia, said his experiences  in the Balkans left him in no doubt that, given the right circumstances,  similar  human rights atrocities could be committed in Britain.  'What  makes a man go for a drink with his neighbour one moment and  shoot him the next? We still don't understand what causes normally  good  people to go over the edge. Until we do, there is the possibility that  it  will  happen here.' The controversial programme argues  that  everyday  prejudice  can quickly develop into full-blown oppression  and even genocide. The first step to tyranny, it suggests, is  the creation of  'in'  and  'out'  groups based on irrational prejudice. The tabloid attacks on asylum-seekers are given as evidence that we are not immune to such blind hatred.

The  new research draws on experiments  such as the one in an Iowa school   two   decades ago when teacher Jane  Elliott split her primary-school class into blue-eyed children, told they were superior, and  brown-eyed  children,  told  they were stupid and unattractive. Within hours the blue-eyed 'in group' were bullying their classmates.

The  researchers demonstrated that little had changed since 1961, when Stanley Milgram,  a young psychologist at Yale, discovered how easily ordinary citizens could become perpetrators of evil. Volunteers were taking  part  in an experiment to test people's ability to learn. They were  then told to administer electric shocks to a stranger behind a screen  when  they  failed  to  perform a simple task of memory, and gradually increase the severity if they continued to make mistakes. To Milgram's horror, two-thirds of the volunteers were  ready to administer potentially lethal doses of electricity when encouraged to do so by a researcher in a white coat.

Professor  Philip  Zimbardo of Stanford University tells the programme that more crimes are committed in the name of obedience than disobedience:  'It is those who follow any authority blindly who are the real danger.' Zimbardo carried out a famous experiment in 1971 at Stanford University when volunteer students were split into guards and inmates  in  a  makeshift underground  jail. The experiment had to be abandoned after the guards began violently assaulting the inmates and several of the prisoners had breakdowns.

'It  demonstrated  the ease and speed with which things can get out of control.  Within  days  the  guards were behaving sadistically and the prisoners  were  acting  pathologically.' But Zimbardo said there were some positive aspects:  the research was used  in  Congressional inquiries into prison riots.

martin.bright@observer.co.uk