Criminal gangs have scaled up a huge drug empire in empty high street stores across the UK, police bosses warned.

Top cops spoke out after several reports of illegal squatters taking over abandoned stores and using them to grow cannabis on an industrial scale. Raids have increased over the past year, with many organisations being discovered.

Authorities have carried out surprise stormings in several locations, including a long shut-down toy shop in Ayr, Scotland, to a closed bank in Welshpool, Powys.

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drugs high street stores
Criminals have been growing cannabis in abandoned shops

The criminals have also targeted other buildings, including cafes, restaurants and night clubs. They even used vacant bingo halls and office buildings to grow and cultivate drugs.

According to the National Police Chief’s Council, the increase in abandoned high street shops and venues has not helped this growing issue. In Newport, Wales, a gang targeted a multi-story former department store to grow more than 3,000 cannabis plants.

Police discovered the plants in the former Wildings department store, which valued to an estimated £2million in street value. In a warning, police have said that any electrician, estate agent or tradesperson that help gangs with conversions will face criminal prosecution.

Chief Constable Richard Lewis, the National Police Chiefs' Council’s national lead on drugs, emphasised the decline of high streets has created a huge opportunity for criminals.

"Commercial properties are attractive to organised-crime groups for a whole host of reasons," he told the BBC.

"Large-scale shops have closed down and therefore the footprint to produce cannabis on a larger scale becomes available. You don't see large numbers of people in the evening any more... neighbours in residential properties would notice things more readily.”

The police decided to crack down on the illegal cannabis farms last year, with around 1,000 warrants issued and 1,000 arrests made.

He added that gangs scout out and target high streets with the highest about of vacancy signs before they choose where to prop-up. The Welsh Retail Consortium carried out a survey last year which found that one in six shops in Wales was empty.

drugs high street
Lower footfall in shops makes it easier for drug farms to go unnoticed

“Let's be brutally honest, we're talking organised crime groups here and the ability to operate on a much bigger scale and level,” said Sergeant Dan Wise from Gwent Police.

The policing duo hope prosecuting tradespeople and estate agents will help stop the gang issues. Lewis said “Of course, most of our tradespeople in the UK do a great job but there are those small minority people who do undertake these types of activities - and we do prosecute them.”

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