Minh Vu Nguyen, 23, Quoc Chien Phan, 23, and Van Ha Nguyen, 29, were all found in the warehouse - which was padlocked from the outside - alongside more than 300 cannabis plants.

Norwich Crown Court heard the unit, on Swanston's Road, Great Yarmouth, was raided by police on July 15 last year.

Norwich Crown Court (Image: Peter Walsh, Newsquest)

Lori Tucker, prosecuting, said the building - which was fitted with CCTV cameras - contained a "maze" of 11 rooms.

She said two of these contained cannabis grows - one with 213 plants between 53cms and 78cms tall - and the other with 103 plants up to 95cms in height.

The court heard the grow was capable of producing between nine-and-a-half and 16.95kg of the drug.

The prosecutor said the street value of the 316 plants found was said to be between £94,800 and £237,000.

She said the remaining nine rooms were "fully set up to produce cannabis" although none were in use at the time.

However Miss Tucker said there was evidence they had been recently harvested.

Quoc Chien Phan (Image: Norfolk Constabulary)

She said all three defendants were found in the living area of the unit which had a kitchen, toilet and shower.

Miss Tucker said phones attributed to the defendants were found and contained images which showed they had been involved in the growing of cannabis at the property.

Va Han Nguyen (Image: Norfolk Constabulary)

The three defendants, all of no fixed abode and who spoke through a Vietnamese interpreter, appeared for sentencing on Monday.

Minh Vu Nguyen (Image: Norfolk Constabulary)

All three had initially denied the offences, claiming they were victims of modern slavery, but all subsequently pleaded guilty to cannabis production.

Judge Andrew Shaw (Image: Newsquest)

Jailing each of the three for 27 months Judge Andrew Shaw said: "This was not a two or three bedroom house converted to grow modest amounts of cannabis.

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"This was an industrial warehouse and 11 rooms inside it had been set up and equipped to grow cannabis"

He said the operation was an "ongoing large-scale operation" capable of producing "industrial quantities for commercial use".

Judge Shaw accepted none of the defendants were able to make money here legally.

But he insisted they had made a decision to come to this country unlawfully "knowing that the only way you could've earned money was by committing crime".

He said it was likely all three would be deported at the end of their sentences.

Charles Myatt, mitigating for Minh Vu Nguyen, said he had come to the country illegally six years ago before being "forcibly encouraged" to come to this industrial unit and water the plants.

He said he was not a "mastermind" but a "foot soldier" in the operation and had been playing a "lesser role" and had only been there a matter of weeks.

Ian James, representing Van Ha Nguyen, said his client came to the UK illegally in 2019 and had worked in a nail bar before begging and then was recruited to the cannabis factory.

He said he had been there for about a month at the factory which had already been set up and was responsible for tending to plants.

Mr James said it was a "two room operation" when he became involved and "never anything else".

Danielle O'Donovan, for Quoc Chien Phan, said he had been "to some extent exploited" without the opportunity for legal work.

© Norwich Evening News