A man who lost his arm when he was playing on train tracks as a boy is spearheading a campaign warning youngsters to stay away from railway lines.

Paul McDonald, of Chippers Close, Tarring village, near Worthing, was lucky to survive after trying to jump on a moving train at Angmering station. He slipped and was pulled under the train. His rucksack got caught and his arm was pulled off.

Now he is urging others to stop playing on trains and the tracks as part of a national campaign highlighting the dangers.

Last year, seven people died in Sussex because they were messing around on train tracks. In June alone, Network Rail reported almost 160 incidents of trespass, vandalism, objects thrown on the lines and trains hitting obstructions. It has reported children playing "chicken" with trains at Bewbush during the past few months.

Paul was 12 when, on July 13, 1995, he took a short cut across Angmering station to get to a friend's barbecue.

He had been jumping on and off moving trains since he was 11, after watching older children do the same.

He said: "It was just one of those things, something to do.

"People also found out the electric current wasn't on at certain times and would dare each other to touch it. We'd have one foot on the live rail and one on the floor which would earth the current. It was the thing to do. We thought we were invincible. It was very risky."

That day the danger caught up with Paul. He tried to jump on to the steps linking two carriages but slipped, hit the back of his head and was dragged under the train.

His backpack was chewed up and it pulled his arm off but in doing so saved his life. He said: "I was a couple of inches from losing my head under the wheels but my arm gave way first. It got my ear, which had to be stitched."

He was taken to Worthing and East Grinstead hospitals where his wound was patched up with a skin graft from his leg.

He is getting involved in the national campaign and will be joined by boxer Amir Khan at HBG Fitness at Oriel High School in Crawley today and tomorrow to launch the No Messin' Live tour for about 2,000 children.

The event is free for all 10 to 16-year-olds and includes a sports, games and music zone, giving them the chance to try out a range of activities from DJ-ing lessons to boxing and skateboarding to the latest computer games.