"Joyriding should not be called joyriding. It can be death-riding, and the more we can explain to people about the dangers of it the better."

The words of Conservative leader David Cameron as he pledged his support to our hard-hitting Drive Now, Live Later campaign.

Since we launched it, our campaign has won many supporters.

They include Lee Corner, father of 15-year-old Joel, who was driving his father's Audi when it crashed into a van driven by Peter Alexander last April.

Joel, his front-seat passenger Daniel Wright, also 15, and Mr Alexander all died.

Both Mr Corner and Mr Alexander's son Stuart signed up to our campaign, and agreed to appear in the video we are making telling about the effect of that awful crash.

Many others have also come forward to offer their support.

They include the police, young "joyriders" themselves, the friends and family of teenagers killed or injured - even the coroner who held the inquest into that tragic accident a year ago.

Mr Cameron, of course, is by far the most high-profile backer so far.

And his pithy comment about how joyriding should be called death-riding sums up perfectly what the campaign is all about.

We applaud him for backing us. We hope that other high-profile figures will do the same.

But it is the teenagers themselves that we really want to reach.

When Mr Corner agreed to back our campaign last month, he said: "If it stops one young kid getting in a car and this happening again, it will have done its job."

Exactly. So if you're a teenager tempted to take your dad's car for a spin, please, please, please stop for a moment.

Listen to those words from a grieving father, and don't do it.