DRINKING orgies in the grounds of Pickering's imposing centuries old castle are angering residents and English Heritage staff.

Now the police have been asked to carry out regular night time patrols after complaints of the picturesque lawned grounds around the castle being littered with hundreds of beer cans.

Jamie Marshall, the operations manager for English Heritage, said: "We have always had a problem of gangs drinking around the walls of the castle, but this summer it's been much worse. We regularly collect three and four big plastic bag full of cans."

Some young people have been able to get into the castle grounds, where they have had drinking sessions and played football.

"We can regularly spend two hours a day clearing up after the gangs and custodians have at times been subject to verbal abuse," said Mr Marshall.

Mike Flynn, the site operator, said: "We see the castle as a community attraction and we are keen to see Pickering people use it as well as the many visitors to the town, but we don't want the late-night drinking gangs and in particular all the rubbish they leave behind them."

On some occasions there have beeen between 30 and 40 youths, said Mr Flynn.

But while the residents are annoyed at their behaviour, they have not wanted to be named because of the fear of reprisals.

"They do feel intimidated. It's a problem which has been around at the castle for about three years but it's certainly been much worse this summer, probably because of the hot weather," said Mr Flynn.

But the gangs have also caused further annoyance by having barbecues and riding quad bikes around the outside of the walls of the castle.

The castle attracts thousands of tourists every year and this summer it is having its busiest for a long time with visitor figures expected to reach 20,000.

Mr Flynn added: "We take great pride in keeping the castle grounds clean and well trimmed but these gangs are just spoiling it and causing a great deal more work.

We are stepping up surveillance and hopefully the situation will improve."

A spokesman for North Yorkshire police said investigations into the incidents at Pickering Castle were continuing and regular patrols were being carried out.