A moving DVD made by Didcot school boys warning about the dangers of fake guns hit home to their classmates at the film's premiere.

Produced with the help of teachers and police, the short DVD featured the fictional story of a 16-year-old boy who was shot by police, because the fake gun he was fooling around with was mistaken for a real one.

It was shown during a special assembly at St Birinus School in front of the boys who acted in the film, their classmates, police and local dignitaries.

Click here to watch the film

Almost every boy at the screening admitted they had come into contact with ball bearing (BB) or replica guns - and some thought that carrying them could "make you look hard".

But by the end of the film, the hall was silent and many boys were wiping away tears of emotion.

Thames Valley Police officers told how they are called to one incident a day involving guns - and more than 60 per cent of these turn out to be fakes.

Chief Inspector Dick Auger, who played the officer who shot the boy in the film, said: "I never joined the police service to shoot a young person who is carrying a toy gun. I don't know if I could even wear the uniform ever again if I did.

"It is really important that young people understand what it means to carry a BB or replica gun. There's a chance you could end up with seven years in prison - or the consequences could be even worse."

The film, called Worlds Collide, is the result of a three-month project involving the school and Thames Valley police.

A script was written by police, but the young actors changed the language to make the characters seem convincing as 16-year-old boys. Mario Da Silva, 16, said: "I thought it was really interesting. I didn't really realise how much a small toy gun can scare people until we started filming.

"And I wouldn't have thought helicopters and police with guns would be called out."

Sunay Rashim, also 16, said: "Acting in the film definitely brought the dangers of carrying a fake gun home."

The DVD also includes a quiz challenging people to spot-the-difference between real and replica guns.

Assistant Chief Constable Francis Habgood said: "Some of the replica guns that we seize from young people are so realistic a trained firearms officer would find it difficult to tell if it was a real gun."

A copy of the film will be given to secondary schools and youth centres throughout the Thames Valley region - and it could soon be sent out nationwide.

Headteacher Chris Bryan said: "If as a result of this film we can avoid one tragedy, if one life has been saved, then surely that will be a good job done."