A CANNABIS factory thought to be the biggest uncovered by Gwent Police was raided at the weekend in a former Newport leisure centre.

Around 20 police officers were involved in the operation at Underwood Leisure Centre on Saturday where 4,000 cannabis plants were found.Three men were arrested on suspicion of the production of the class B drug and were each charged with the offence yesterday evening. They are due to appear in magistrates court this morning.

Leading the operation was Gwent Police Sergeant Nicola Williams, who explained that officers forced entry at the front of the building and uncovered the plants, with the majority in the sports hall and side rooms.

She said: “I believe that it is one of the largest cannabis factories uncovered in Gwent and although the value of the plants is still being worked out, we estimate that it will be over the £1.1 million mark.”

Police arrived at 10.30am after they received information of cannabis production at the site and remained on the scene overnight.

The 4,000 plants are in various degrees of maturity and Crime Scene Investigation teams were on site on Saturday to collect evidence before the plants were to be removed.

Sgt Williams added: “Gwent Police will always take a zero tolerance attitude to cannabis production and we look to the community in helping us to gather intelligence to help us to target such sites.”

Residents told the Argus that they had seen the vents of the centre being sealed to stop any produce emitting from the site.

A resident of Waltwood Road who did not want to be named, said: "You could smell it now and again but I never thought it was a cannabis factory.”

The leisure centre has been closed since last year as part of cost cutting measures by Newport Council.

James Tiffney, a resident of Acorns Street, said: “I have smelt something before but just thought it was teenagers smoking.

“It’s quite shocking."

He added: “We walk Rocky, our dog around there – there are never any lights on. It used to have one padlock on the door and recently it’s had two.”

Anyone with information should call Gwent Police on 101 or Crimestoppers 0800 555111.