Two men have admitted producing thousands of pounds worth of cannabis at an industrial unit.

But Ian Walding, 42, and Richard Lambert, 55, still face a trial after prosecutors claimed today that the enterprise could turn out many tens of thousands of pounds worth of the drug.

The men admitted producing cannabis at a warehouse in the Porte Marsh industrial estate in Calne.

They say they only grew about 6kg of the drug worth about £19,000 but prosecutors insist that would only cover the overheads of the operation.

As a result the men are to face a trial of issue where a judge will decide on the true value of the drugs growing enterprise.

The men had pleaded guilty to producing cannabis between the start of April 2007 and Monday September 8 last year at an earlier hearing.

They also admitted acquiring criminal property in the form of cash over the same time period.

Walding, of Hinton Parva, also admitted possessing cannabis and Lambert, of Welling Garden City, Herts, having amphetamine sulphate on September 8.

Colin Meeke, prosecuting, told Swindon Crown Court: "We are kilos apart," after saying what the men admit to producing.

Recorder Nigel Seed QC adjourned the case for a hearing in the autumn and released the men on unconditional bail.

Police believed the drugs factory was one of the largest found in the area when they raided it is September.

Cannabis was being secretly nurtured at the industrial estate in a building cunningly disguised as a Drakes Ceramics warehouse.

Drugs squad detectives swooped on another unit in Harris Road and are believed to have found another growing factory of a similar size.

Forensic teams were forced to call in reinforcements to handle the amount of cannabis as they laboriously took apart the factories.

A flat bed lorry was also seized from outside the ceramics businesses.

Police who went into the warehouse said cannabis was growing from wall to wall and floor to ceiling.

Charlotte Newman, a worker at K & R Chem-Dry, a carpet and upholstery cleaners opposite the scene, had no idea what had really been going on over the road.

She said: "it is a real shock, you wouldn't have thought something like this was going on down here.

"I had wondered what was going on there, because I've never really seen anything happen.

"I look at the place all day and never saw anyone come or go and certainly never saw any ceramics.

"To think they had got away with this all that time."

Police who stormed the scene said cannabis was growing "from wall to wall and floor to ceiling", with a street value that could climb into the tens of thousands.