Oral sex in XXX audience

The notorious Spanish stage show XXX faces a new threat of prosecution today after two people in the audience openly engaged in oral sex during its second night on the London stage.

Tuesday's opening night at Riverside Studios had already caused controversy for featuring some of the most explicit scenes ever seen on a British stage.

A man in the audience was apparently given oral sex by one of the actresses, though the company, La Fura Dels Baus, later claimed the man was a "plant" who used a prosthesis to fake the sex act.

Last night two people from the audience had oral sex in the aisle of the auditorium, encouraged by one of the actors.

Evening Standard reporter Rebecca Mowling, who was sitting only inches away, said: "The people involved were apparently genuine members of the audience. It seemed as though they were strangers."

The sex act, prompted by cast member Pedro Gutierrez, broke new barriers in a show which already features simulated sex on stage and genuine hardcore sex on a video screen.

The latest female participant, who later gave her name as Mistress Poppy, 33, insisted she had no connection with the theatre company and that she was a "professional dominatrix" and porn actress. After the show she said: "I've done this sort of thing before, in porn films and live sex shows, and I would have loved to go up on stage and have full sex there too."

Her sexual partner also denied he was taking part in a preplanned exercise. The 29-year-old German man, who would only give his name as Michael, said: "Everyone in the audience wanted to do what I did."

The controversial play is based on the Marquis de Sade's 18thcentury book Philosophy In The Bedroom and tells the story of the sexual initiation and degradation of a teenage girl by two men and a female dominatrix.

The Vice Squad passed the show as suitable for over-18s after viewing a tape and attending the opening night, but a senior Scotland Yard source today said police would examine the latest evidence.

A Home Office spokeswoman said: "It does not make a difference if it was a member of the cast or a member of the audience who was involved. Sex in public is an offence."

There were no early departures among the audience, who had paid £25 each.

Chris Horsfield, 43, a fashion designer from Surbiton, said: "The show was fantastically successful at attacking many of the taboos society holds about sex today."

His partner Rigine Delahoy, 44, a jewellery designer, agreed: "I found the show delightful, although I wouldn't recommend it for my 21-year-old daughter."

Joanna Poulton, 34, a dance teacher from Hammersmith, said: "It was nothing like the kinds of shows you might find in Amsterdam or Prague. It was nowhere near as shocking."

Darran Hunt, 50, from Plaistow, said he had been led to believe the show would be erotic but had found it "absolute rubbish".

"I would have preferred a night out in Spearmint Rhino," he said.