Avon and Somerset Police evicted 40 squatters from the Clifton Wood House in Bristol following the complaints made by neighbours over noise levels during a party on Saturday night.

Violence broke out as police tried to eject squatters who took over a £3million mansion and intervention led to the arrest of 11 people – nine people for public-order offences and two for assaulting officers.

“We went to the property this morning following on from an incident last night, which was a party at the premises, and we had a number of complaints. This morning two neighbourhood officers went to do some follow up inquiries and came under attack with objects thrown from the roof,” said police spokeswoman.

Eyewitnesses claim that 17-year-old boy suffered a broken nose during the eviction and a pregnant woman was dragged from the mansion. During the operation, Constitution Hill and Clifton Wood road were closed.

One of the squatters, Raoul Duke, 22, claimed that police behaved “horribly” with people, saying “We were having a private birthday party when 20 police came into the living room and tried to turn off the speakers, hitting a few people on their way through. The Police were pushed back and they retreated but later on six vans and loads of cops arrived and forced us out.”

He denied the charges that squatters had been creating problem from past two months, saying that they had a good relationship with most of the neighbours. However, neighbours have claimed the squatters have been hitting golf balls off the roof and holding late night parties.

The mansion, legally owned by local businessman Petros Birakos, is grade II listed property with eight bedrooms, four bathrooms, an indoor swimming pool, vaulted cellar and a gym. The grand mansion is currently owned by the Royal Bank of Scotland and 24-hour security will be brought in to prevent any future break-ins.