A teenager had to be airlifted to hospital and his dad was left with a broken nose after more than 100 teenagers gatecrashed a 16th birthday party on Saturday night.

Dave and Susan Worthy told of the horror that awaited them as they returned to their home in Brewer Mead, Chippenham, where son Christopher was celebrating his birthday.

The pair had been for a meal in the nearby Old Lane pub with their younger son Richard, 14. They had planned to return at 9pm and watch a DVD in their bedroom upstairs while Chris, a Sheldon pupil, and his friends celebrated downstairs.

But the party turned to chaos as scores of uninvited youngsters turned up after an invitation was posted on the website YouTube.

Despite 18-year-old Stephen Worthy manning the door, the teenagers managed to get into the house and raid the alcohol cupboard, stealing whisky, wine and champagne.

Mrs Worthy, a nurse, said: "We left at about 7pm and about an hour later, Stephen called us and asked us to come home. We rushed straight back.

"As soon as it went pear-shaped the police came and the kids went home. There were too many for us to sort it on our own but with the help of the police we managed to calm it down."

Several fence panels were broken as teenagers fled.

Within a couple of hours, the trouble flared again as another group of uninvited guests turned up at the semi-detached house.

Mr Worthy went outside to try and get rid of the ten-strong gang and was punched in the face. Son Stephen stepped in and was set upon by the gang - who started punching and kicking the teenager.

They managed to make their way inside the house and shut the door. Mrs Worthy said: "We were scared stiff then there was a loud bang and the windows smashed.

"I was terrified. I thought they were going to kill us."

By the time police arrived the group had fled. Stephen was rushed to Great Western Hospital in Swindon by air ambulance with suspected spinal injuries while his dad was taken by road ambulance. Both were released in the early hours of Sunday.

Police arrested six teenage youths, for offences ranging from public order offences to causing grievous bodily harm.

All have been released on police bail.