"It's all about Cassie Cowan - a nice girl from a nice Gwent valleys family - who kills four people on the road because she used her mobile phone and lost her concentration for a few seconds."

It's with these words that the police force from Gwent, a region of south Wales, introduce their mini horror film. Directed by local lecturer Peter Watkins-Hughes and acted out by amateurs, the scene from a 30 minute educational video for school children, is soon to be broadcast on BBC Wales as an advert.

The somewhat radical strategy comes in response to evidence which proves that 18-24 year-olds' reaction times are 35% slower when reading or writing a text message, meaning that the effects are therefore potentially just as fatal as drink or drug driving. And half of young drivers do it. The message is not falling on deaf ears - the video has already got almost 1.5 million hits on YouTube.

Warning, you may find the video upsetting.

The sorry tale of Cassie Cowan

“The film should be shown to young people when they pass their driving test”

Mick Giannasi is Gwent police chief constable. He's also a member of the national Association of Chief Police Officers (ACPO) and a driving safety specialist; referred to by the UK press as "Britain's top traffic policeman".

I want as many young people and families as possible to see this film so that they understand the consequences of such accidents on small communities like their own. The film shows just how dangerous it is to be irresponsible behind the wheel. It doesn't only show the immediate consequences of the accident, but also the consequences for the family, the community, and the girl herself. People in Canada have contacted us to say how moved they were by the clip. A young driver from Cornwall sent me an email to say that the film should be shown to young people when they pass their driving test. I told him that that was exactly what we - the fire service, the ambulance service and the helicopters - were hoping for when we were shooting it."