The man told her to drive away but the Citroen Saxo stalled and the group of teenagers surround the vehicle, threw bricks at it and kicked it.

Both wing mirrors were ripped off and the windscreen, rear and side windows were smashed. One youth even opened the driver's door before the terrified woman managed to pull away.

The damage to the car was so extensive that it has since been written off and its owner has been left with a £350 insurance excess bill.

The 42-year-old woman, who has asked not to be named for fear of reprisals, said: "I was driving through the centre of Heckmondwike and I saw a gang of about 15 to 20 youths chasing a man.

"Suddenly he jumped into my car and said 'drive', but as he did I took my foot off the clutch and stalled. It's a diesel so it takes a while to get it started again, but then the youths came and surrounded the car.

"They threw bricks through the front and back windscreens and side windows, started kicking it and tore both of the wing mirrors off.

"I was scared. I didn't know anything about what had happened to provoke this and I thought, 'what have I done, I've just pulled up at the lights'!"

She said the group came from the direction of Firth Park towards the Northgate traffic lights.

The woman was on her way to collect her son from Ravensthorpe when the incident happened at about 8pm on Monday May 5.

Mechanics said the six-and-a-half year old red Saxo was not economically viable to repair.

The woman, who lives in Heckmondwike, said: "I thought the gang were going to beat the guy up and I'd never want to see anyone get hurt, so I'm glad that didn't happen. But he's fine and I've been left without a car and am £350 down."

The woman took the 49-year-old man to Dewsbury Police Station after she had picked up her son.

Later that evening she discovered a bump on her head with pieces of glass in it, and spent almost four hours at hospital.

She said: "The first thing the scenes of crime investigator said to me was that I should have had my doors locked, but if I had the man would have been beaten up and I don't know what would have happened.

"I just want people to be aware when they're driving of what can happen."

A West Yorkshire Police spokesman said the chase happened after a 17-year-old girl, who was with the 49-year-old man and a 26-year-old man, was assaulted by a teenage male gang member.

He added: "The man was chased towards the Northgate area by a number of the teenagers.

"To escape those chasing him the 49-year-old man got into a red Citroen Saxo, driven by a 42-year-old woman who was not known to him. The vehicle was then attacked by the teenagers before being driven away."

Inquires are on-going and any witnesses or anyone with information is asked to contact Pc Richard Terry on 0845 6060606 or Crimestoppers anonymously on 0800 555 111.