Detectives found vats of bubbling chemicals in a barn when they swooped on a suspected £20 million drugs factory, a court heard.

Officers discovered containers of powder, bottles, pans, funnels and other paraphenalia scattered around the isolated farm when they raided it in July last year, a jury at Lewes Crown Court was told.

Police described on Friday how a family living at Bugsell Mill Oast, Hurst Green, near Robertsbridge, converted household appliances into machines capable of producing amphetamine.

The court heard chemicals which could be used to produce 660 kilos of the drug were found.

Forensic expert Ian Griffin for the prosecution said: "There were two rooms which were being used as part of the production process.

"The large room was where most of the action, if I can call it that, seemed to take place and a smaller back room.

"There were large quantities of chemicals and large quantities of glassware and equipment with solids and liquids in them.

"Some of the equipment was turned on when I entered the barn and something was in the middle of being filtered."

Mr Griffin told the court he had found amphetamine in the barn.

He said: "There was plenty of residue and finished product about.

"From the chemicals, glassware, equipment and substances we found in the barn I concluded amphetamine sulphate was being produced on the premises and was being diluted with lactose."

He also found home-made drug-making apparatus including a steam distiller for filtering liquid.

Mr Griffin said: "There was steam distillation apparatus. It had a Baby Belling-type heater with a pressure cooker on the top of it.

"The pressure cooker acted as a steam generator.

"But instead of working as a pressure cooker, it had been modified so steam escaped from a valve and went through a pipe into the liquid. That helped distill the liquid in the flask.

"I certainly detected amphetamine in the liquid. In my opinion this was the final stage but one in the process - the steam distillation of the amphetamine oil."

In total, 811g of pure amphetamine was found in the barn, estimated to be worth between £5,000 and £150,000, the court heard.

The court heard how Kevin Hoare was arrested on July 18 after delivering a box containing 1 kilo of pure amphetamine to Graham Pierce's London address.

Pierce was arrested on the same day, giving his job description as a "professional gambler".

Kevin Hoare, 46, the owner of the farm at Hurst Green, his two sons, Adam and Russell, both 20, his girlfriend Tracey Thacker, 35, of Vicarage Way, Hurst Green, and Alan Smith, 52, of Frewin Close, St Leonards, are accused of making more than £20 million worth of amphetamine sulphate and passing drugs to Graham Pierce, 41, of Streatham, south London, to sell.

All deny conspiracy to produce a controlled class B drug. Kevin Hoare and Pierce, 41, deny conspiracy to supply a controlled class B drug.

The trial continues.