Bookies wary as Big Brother 3 begins

The new house has more double beds

Big Brother is returning to UK TV screens on Friday night - with the identities of the 12 contestants so far being kept a closely-guarded secret.

The new Big Brother house is in Elstree, Hertfordshire and boasts more double beds and a swimming pool, instead of the hot tub which featured in the previous series.

The housemates' identities are being kept secret until the programme goes on air at 2100 BST - although Channel 4 is teasing viewers with silhouettes of possible contestants during commercial breaks.

Davina McCall will host the series for the third year, but there will be changes to the inmates' regime - including more contestants, tougher rules and new challenges.

The house boasts a swimming pool

No books or musical instruments will be allowed in the house, in a bid to produce more interaction between housemates.

They will be set tough tasks, which will be followed on a live show on Saturdays.

There will also be no World Cup coverage inside the house.

Bets

The show, which has been a huge ratings success in the past, puts the housemates under constant camera surveillance and they are not allowed to leave the house.

Each week they must nominate people for eviction, with the viewing public having the final say.

The last person left in the house will win £70,000, and of course will find their face in many national newspapers.

Programme makers are hoping the new restrictions will force the inmates to get to know each other better - and there has been heightened speculation about whether any of the housemates might finally sleep together.

Bookmakers have already slashed their odds on the chances of contestants having sex, after signs that punters might have inside information.

The outside of the house in Elstree

Coral reduced its odds from 20-1 to 7-1 to 2-1 in one day after it was inundated by bets.

"We are wondering whether people with inside information about the contestants know that sex is a distinct possibility this time round," said the bookmakers' spokesman Simon Clare.

"If the money is any guide you can expect 12 nymphomaniacs to be let loose in the house tomorrow night."

Some 150,000 people contacted Channel 4 for the chance to be part of the team for Big Brother 3.

Programme makers watched more than 10,000 video entries over eight weeks, auditioning some 2,500 applicants.

Shortlisted candidates underwent police checks and were required to see a psychotherapist.

Big Brother 3 is on Channel 4 at 2100 and 2335 BST