When police were called to a semi-derelict building in Gloucester they found an industrial-scale cannabis factory.

Inside were 500 cannabis plants said to be capable of producing almost half-a-million pounds worth of the drug.

It was a discovery which also netted the gang of six staffing the criminal operation and landed all of them in the city's crown court where they were jailed for a total of five years and five months.

All the men had entered the UK illegally, usually in the back of lorries at different times, and had sought employment wherever they could to pay back their fee to the human traffickers who got them into the country.

Prosecutor Janine Wood told the court that most of the men had followed instructions to go to an address in Spa Road in Gloucester to 'cut flowers' - a euphemism for the cultivation of cannabis plants.

The court was told that the cannabis factory came to the police's attention on September 5, 2019 when a member of the public reported that there was a strong aroma coming from the Spa Road property.

Mrs Wood said one of the men was found when police entered the property: "In the loft they saw that an internal wall between the properties had been removed and they could see into the neighbouring house and could see a large number of cannabis plants.

"With the help of additional police officers the front door of the left hand property was forced open. The five other men were found in the basement.

"The officers realised they had discovered all the paraphernalia for a drug operation from the hydroponics and the foil extractor systems to sustain an industrial cannabis factory."

The court was told that every room of the house was being used for cannabis growing. There were juvenile plants and mature plants and some that had been stripped of their leaves ready for harvesting.

"There was a total of 546 plants that if they had all reached maturity would have had a street value £458,640," added Mrs Wood.

"This was an ongoing enterprise operated by others with the six Albanians having a lesser role at the site."

The Judge, Mr Recorder Gordon Bebb QC, was told that investigations had drawn a blank on who was behind the gang.

The six defendants, all Albanian, Xhuljano Bircaj, 28 Glen Rami, 28, Ervin Bajraktari, 31; Besmir Bajraktari, 32, Enea Sela, 24 and Andi Sela, 31, all of no fixed abode, pleaded guilty to conspiracy to produce cannabis between September 1 and September 6, 2019 in Gloucester.

Lee Mott for Andi Sela and Bircaj said: "Both men were hoping to make a better life for themselves. Bircaj arrived in this country expecting to be a cleaner while Sela was hoping to marry the girl he had met in London in March of last year.

"His construction work had dried up when he took on this job."

Alun Williams for Ervin Bajraktari and Besmir Bajraktari said: "On arrival in Britain they were exploited by their traffickers and ordered to work where they told to pay off their fees. Both men were told to go to Gloucester to 'cut flowers.'"

Charlotte Surley for Enea Sela and Rami said: "Rami had been in the country for three years before he was arrested. He had worked in the construction industry, at car washes and undertaken gardening jobs.

"Sela had only been in the UK for a couple of months. He had been an IT student and a tour operator in Turkey. He spent £13,000 getting to this country and is extremely apologetic about his actions."

Recorder Bebb said to all six defendants: "This was a professional operation involving two town houses in which one of them was taken over for production of cannabis.

"You used professional equipment that included an extractor system, specialist fertilisers and used artificial lighting.

"The electricity supply was bypassed. Every room in the property was used. This would have been a high profit production line, which was an ongoing operation that only ceased because of the police's intervention.

"Some 546 plants at different stages of development is a significant operation and I have considered whether it was in effect being done on an industrial scale.

"In my view it has elements of both categories, but the equipment used is of professional quality for an industrial concern.

"You are all illegal immigrants and took part in the cannabis production to pay off the costs of coming to this country and no doubt in due course to make money for yourselves.

"However the offending is so serious that only a custodial sentence will be justified. You all share the same mitigation of being of good character."

The judge sentenced Bircaj to a year in prison. Enea Sela and Rami were given a 10-month prison sentence while Ervin Bajraktari; Besmir Bajraktari and Andi Sela were sentenced to 11 months in custody.

The court was told when the defendants had completed their sentences they would probably be deported.

The judge ordered for the forfeiture and destruction of all the plants, the drugs and associated paraphernalia.