There can be few activities as appealing as sitting in a quiet country pub, listening to the gentle tinkle of a stream and supping a warm pint. But this pleasure is under threat.

High property prices have encouraged chains to sell off less-profitable hostelries, mostly country pubs and back-street bars, and concentrate on fashionable town centre operations.

According to Camra, the Campaign for Real Ale, 20 rural pubs are closing across the UK each month.

The majority are being turned into large country houses, which can be sold at a premium rate.

Launching the first National Pub Week this week, Camra also claimed one in four people never visited the pub, with that figure even higher in the South- East.

Last month, Lewes District Council gave permission for the Sandrock Inn, Ditchling, to be converted into two houses, despite 700 signatures on a petition against the plans.

A spokesman for Clifford Dann, agents for the developers, said the pub had not made money for years. "If you don't use it, you lose it," he remarked.

Camra said specialist pub companies were concentrating all their efforts on turning town centre pubs into large, soulless bars.

Micro-breweries are also struggling against the might of the big pub companies.

The Evening Star in Surrey Street, Brighton, brews its own beer so has a ready market place.

Landlord Matt Wickham said it was hard to find other outlets to sell the brew.

He said: "The big pub companies are owned by Japanese banks who are making it difficult for smaller breweries to provide beers for them.

"We sell our beer to some other pubs but getting others interested is difficult because they are not allowed to provide it, even if they want to.

"Quite a few places just stock Harvey's or Director's. It is quite rare in the middle of Brighton to find a range of beers.

"We have our own brewery on site, although we are moving it to a purpose-built place near Burgess Hill and always have three or four guest beers on.

"Quite a few pubs are getting turned into houses. But we have not lost trade ourselves, particularly because we get people travelling a distance for our beer."

Out of town, the problems are even more pronounced. The British Beer and Pub Association said half of all villages were without a pub.

The Sandrock Inn is the latest in a string of rural and semi-rural pubs to be targeted by developers.

A spokesman for Lewes District Council's planning department said there were two remaining public houses in Ditchling, which was adequate, despite the village falling within the proposed South Downs National Park boundary and the expected rise in tourism.

Nikki Chapman, of the Ditchling Society, said the inn was an "important community amenity" and its closure would damage the village. However, councillors felt their hands were tied. No one from pub owner Ditchling Inns was available for comment.

But a spokesman for Pubmaster, one of the national pub chain giants, with 3,200 outlets across the country, said it had a better record than its rivals, particularly at promoting small local breweries.

He said: "We do take beers from 30 regional and micro- breweries and 300 publicans are part of a cask ale club, which allows them to buy from local sources."

Jerry Marchant, a spokesman for the Arun and Adur branch of Camra, said a number of local pubs had been converted into homes.

He said: "The nearest to here that closed was the Black Dog and Duck at Bury, near Arundel. The villagers campaigned to keep it as a pub but it got the go-ahead.

"Nowadays, country pubs either have the option of selling as a private house or they turn into restaurants.

"Country pubs are dying and town pubs are being taken over by big companies. You can't go for a quiet little crawl in the centre of Worthing or Eastbourne now because they are full of big pubs for kids. The only places worth going are on the fringes.

"In smaller towns like Arundel and Steyning there are still some decent pubs going because there aren't enough kids."

Diversification appears to be the key for country pubs that want to stay profitable. Some have introduced other community services, such as hairdressing or post office facilities.

The most popular option is turning them into eating establishments and Camra found in a recent survey that quality of food was one of the most important factors in the minds of pub-goers.

One such pub is the Gun Inn at Findon, which was threatened with closure after developers bought the land and applied to turn it into flats. Landlord Nick Georgiou said: "A property developer bought the pub from Whitbread with the intention of knocking parts down and building at the back.

"There was a campaign in the village and 2,000 to 3,000 people signed a petition. It is Grade II-listed, 13th Century, oak and timber-framed building and it would be sacrilege to change it.

"I was running the Spotted Cow in Angmering at the time and heard about it. I approached the developer and got the freehold for the pub and they got permission for five houses at the back.

"The development did not really affect the pub and we are a thriving business now."

Mr Georgiou said he had had to change the nature of the business to remain profitable.

He said: "I'm a food person so it is a restaurant pub now and is really focused on food.

"In fact, we've just had planning permission to double the size of the kitchen.

"We've kept the bar and have four real ales on tap. But we had to get rid of the pool table, the games room and the juke box or we would not be able to keep up the repayments on the mortgage. There is no way we would survive otherwise."