The owner of the 17th century stately home Halswell House was horrified as what he thought was a high-end masquerade ball turned into a sex orgy.

More than 350 well-heeled partygoers, who had arrived in Porsches, BMWs and Aston Martins attended the party, and held lit candles as they watched a mysterious man in a red cloak and two women in lingerie perform on stage.

When the clock struck midnight, the guests stripped down to leather pants, corsets and suspenders. Within minutes, they began having sex.

The Somerset property was rented for £9,000 for the night, from what the owner, Grahame Bond, later found out to be a Dutch-vased adults-only entertainment group.

Bond, who had bought Halswell House for £1.94m in 2004, said he was disgusted by the party and was forced to send soem of his teenage staff home because of the explicit activities, the Daily Mail reports.

He called the police but officers told him they couldn't intervene as it was a private function between consenting adults.

Bond, 45, said the evening suddenly turned into an orgy "as if a switch had been flicked on." He said: "The party started normally and it all seemed pretty harmless - people were drinking but everyone was very well behaved and pleasant."

"The whole group were dressed in these great costumes and it looked exactly like something out of Eyes Wide Shut," Bond said. "But then one of the organisers announced: 'The moment has come. The spell has begun' and everyone behan kissing and having sex."

Bond said he was stunned as he suddenly noticed a couple "at it" at the window sill. "When the haze from the dry ice in the disco room cleared we realised it was going on everywhere," he said. "The guests were all public-school types and I jokingly said to one: 'I suppose you are a High Court judge.' He replied: 'You're not far off the mark.' "

The partygoers arrived at Halswell House at 9pm on Saturday, and danced to music provided by a DJ until the orgy began at midnight. Bond immediately sent two 19-year-old waitressed home, and the party continued until the bar closed at 3am, and the guests retired to their rooms.

The Dutch company had sold tickets at £65 apiece and the advert on their website read: "LittleSins brings you at an (sic) exquisite manor house. A new luxury and even more exclusive editioni of the cape and mask party in the UK near Bristol. COUPLES & FEMALES ONLY! No Single men!"

Bond said: "When they booked the party they did say 'it's got a dating aspect to it.' I'm just taking it in good humour because it was supposed to be a private party." He added: "I called the police but they said that as it was a private party there was nothing illegal about it."

[via DailyMail]