Bookmakers believe Michelle, 23, did have sex with Stuart

Stuart Wilson and Michelle Bass spent an hour together beneath the dining room table, off-limits to cameras.

A Big Brother spokesman said the show was not commenting on the incident.

Playboy TV said it was ready to reward Michelle and Stuart with a �100,000 contract to present a show on the soft porn channel Climax3.

Bookmakers including Ladbrokes and Paddy Power have paid out thousands of pounds to punters after acknowledging that the pair probably did have sex.

Stuart, 20, spent an hour with Michelle beneath a table

"We're convinced of the evidence, having seen last night's footage and the E4 feeds," said Ladbrokes' spokesman Warren Lush.

"There is also a conversation between Michelle and Shell, being shown tonight, that helps to confirm this."

Ratings

About six million viewers - nearly a third of the viewing public - watched Stuart and Michelle's antics, according to unofficial overnight figures.

Ladbrokes and Paddy Power said they had taken several hundred bets each at the beginning of the series that a couple would have sex inside the Big Brother house.

"We always thought it was going to happen," said Mr Lush at Ladbrokes. He said the company had paid out a small five-figure sum to hundreds of punters after accepting early bets at even money - with the price later falling to a 1/2 odds-on certainty.

At a similar stage Paddy Power had offered 2/1 - falling to evens - on a couple having sex, leaving the bookmaker a few thousand pounds out of pocket.

"The sex may have been good for Stuart and Michelle, but it certainly wasn't good for us," said a Paddy Power spokesman.

The four contestants facing eviction this week are Daniel Bryan, Nadia Almada, Victor Ebuwa and Jason Cowen.

Jason is the 1-10 favourite to be voted out by the public this Friday, following Somali-born Ahmed Aghil who became the fifth to go last week.