It was built to house one of Sussex's most prosperous families but for more than 20 years it has stood empty.

Stanmer House, a Grade I-listed Georgian mansion outside Brighton, has been largely forgotten as the county's other heritage sites are preserved in painstaking detail.

But it has suddenly becoming a working building again with the filming of a modern Channel 4 opera featuring a cast of children.

The large rooms, rural surroundings and nearby greenhouses have made it the perfect location for the televising of Zoe, a specially-written production focusing on the problems of genetic engineering.

Producer Simon Flind said: "We don't have any power or water in the house because it's been out of use for so long.

"But there are so many rooms and the architectural is beautiful.

"Everything we needed was on site. There were even laboratory scenes we needed to film, so we went to the greenhouses at the back and it worked really well."

Zoe has been organised by the education unit at Glyndebourne.

A cast of ten children play the main parts. The main character Zoe is the daughter of a mad scientist.

She grows up to become an anti-genetic science protester who eventually kills him and goes to prison.

Simon, who lives in Glynde, said: "A lot of people think opera is a bit elitist. I think that's a bit misleading.

"This year, rather than film two black-tie operas at Glyndebourne we have decided to use a different location for one of them.

"A lot of young people will be able to watch it and it should help add to its popularity.

"By putting it on TV and shortening the opera by 30 minutes it makes it more like a film in style and length. By working on this theme it should attract more viewers."

The cast pre-recorded the music to Zoe, which lasts 90 minutes, in a London studio.

The filming has to be synchronised with the voices and made to exactly the correct length for scenes.

Stanmer House, built in 1720, has had up to 100 cast, chorus and crew working in it at times during the three-week filming, due to end next week.

It was partially-restored by Brighton and Hove Council three years ago and is due to be fully renovated soon.

Overlooking Stanmer Park it was once the opul-ent home of the Pelham family, the Earls of Chichester.

Brighton and Hove Council rented the property out to the film company making Zoe after location manager Gavin Northover found it empty.

He said: "It's ideal. It's empty but not completely derelict.

"There are lots of good sites around Brighton which we could use for filming.

"There's not the same hassle and expense as you get in London.

"Hopefully we can use the area more in the future. It would be excellent to get a major film star to do some work here."

Emily Gilchrist, 18, who has just left Moira House School in Eastbourne, plays Zoe.

She said: "It's an absolutely fantastic place to work.

"It's the first time I've ever done any filming and I can't think of anywhere better to start."

Zoe will be screened on Channel 4 on December 9 at 6pm.