Police break up 'Facebook party'
Emergency workers were pelted with missiles as they broke up a mass party at a house in central London.
Hundreds gathered at the four-storey abandoned property in Park Lane, some people climbing on the roof, sparking fears the building may collapse.
As police, ambulance and fire crews tried to get people to leave they were pelted with bricks, bottles and slates.
Police, who said Thursday night's gathering was arranged via Facebook, are working to trace the organiser.
Emergency services were alerted at about 2300 GMT after reports that a large number of people had gathered in the property.
A police spokesman said: "A large number - in excess of 2,000 persons - were holding some form of 'event' or 'gathering'.
Party goers describe the big event
"People were seen climbing on to the roof and police were concerned that the roof and structure of the building was unsafe."
He continued: "Police attended but were unable to access the building after some of the people inside and on the roof threw missiles, bricks and bottles at them.
"Police used loud hailers to ensure people inside understood they needed to leave the building and the area for their own safety."
Most people had left the building by 0045 GMT.