A yob laughs as he stamps on a car windscreen and a boy is threatened with a knife in internet videos that appear to have been filmed in Oxford.

The disturbing footage is available to view on the popular internet site YouTube.

In one video entitled "Phillip murks a car", a boy dressed in a grey hoodie and dark trousers jumps on the bonnet of a Peugeot 406 and attacks its windscreen.

As his feet crack the glass, he and the individual filming the vandalism can be heard laughing before they run away.

The video is captioned "A pro at car-window smashing".

The video is tagged with key words to help website users find the footage - including Oxford, OX3, OX4, Donnington and Barton.

It is one of two that have been uploaded to YouTube.

In the other, a knife appears to be brandished in front of a youth.

The 19-second clip sees a teenage boy forced to say "Phillip's the best".

"I didn't do nothing," he protests.

A boy off camera is heard to reply "We'll lick you (hit you) straight in the face - you'll get more licks until you say it."

The boy filming the incident then holds a knife up.

The clip is captioned "Phillip vs Tino in Donnington" and again is tagged with the words Oxford, OX3, OX4, Donnington and Barton.

Sue Frizzell, an events co-ordinator at Donnington Doorstep Family Centre, said she hoped the videos could be used as evidence against their creators.

She said: "If they are stupid enough to show their faces hopefully the police can deal with them."

A YouTube spokesman said: "YouTube is a community site used by millions of people in very positive ways.

"Sadly, as with any form of communication, there is a tiny minority of people who try to break the rules.

"On YouTube these rules prohibit content like pornography or gratuitous violence.

"When people see content that they think is inappropriate they can flag it and our staff then review it.

"If the content breaks our terms then we remove it - and if a user repeatedly breaks the rules we disable their account.

"If the police ask us for information, we will cooperate, so long as they follow the correct legal process the Government introduced."

Police spokesman Vicky Brandon said: "The information has now been passed to the neighbourhood sergeant for Barton, Risinghurst and Sandhills and he will look into it."