THE owners of a suspected brothel in Darlington were among seven people being questioned by detectives last night following an extensive police investigation.

Police made four arrests and confiscated a haul of items as they raided the Pleasure Zone sex shop, in Darlington, and an address in Cumbria yesterday morning.

The swoop followed surveillance of the high-profile business in Darlington's High Northgate, which also offers escort services.

Two of those in custody were believed to be John and Lesley Middleton, the husband-and-wife team who own the shop.

Two others were arrested following the raids - a woman in her 50s, in Darlington, and a man in his 40s, who was being held in Ferryhill, County Durham. All four were still in police custody last night.

A further three people - two women and a man - were being questioned by police.

Mr Middleton has always insisted that Pleasure Zone - which includes an escort agency, sex shop and massage parlour - was a legitimate business. But last night a police spokeswoman confirmed that detectives were investigating the Pleasure Zone as a suspected brothel.

Mr Middleton, of Kirkby Stephen, Cumbria, turned the High Northgate premises into a sex shop after closing down his double glazing sale-room, C Thru Windows, which occupied the site.

The shop sells maids' and nurses' outfits, edible knickers and other adult products, such as sex toys.

In 1999, the unlicensed sex shop, which marketed itself as a fun, adult clothes and accessories shop, branched out into the escort and massage business. Mr Middleton's website advertises female escorts aged 18 to 40, who are pictured in various poses, wearing French maid outfits, PVC catsuits and basques.

The "in-house escort service" is advertised as costing £100 for an hour. The website also advertises a venue "immediately off the A1 in North Yorkshire".

The website says the service, which also offers male escorts, "aims to please you so much you cannot resist making return visits".

But according to a former employee, workers were asked to sign a contract stipulating that no sexual favours would be included in escort deals.

Mr Middleton said last year that the business would be legitimate and legal.

He said: "We all know that escort and massages can cover anything, but there will be no sex involved. It will be purely dinner dates."

Mr Middleton announced two years ago that he was planning to open a members-only lap-dancing club in North Yorkshire, which would have included a massage room, bar and restaurant - although the plans came to nothing.

He also caused controversy in 2001 by placing a 10ft sandwich board on the side of the A1, advertising the agency on one side and the sex shop on the other. Councillors on Hambleton District Council said the advert was distracting drivers passing Baldersby, in North Yorkshire.

The Middletons are registered as directors of several businesses, including dormant company Dare Devils Arena, Middleton Enterprises, which is in liquidation, and Dion Limited, an advertising company, as well as Pleasure Zone, which is registered as "retailers of women's lingerie".