Police were initially contacted on October 7 after a passer-by reported a strong smell of cannabis from the derelict Millom venue on Crown Street.
Carlisle Crown Court heard that officers executed a warrant two days later.
Present inside were Albanian nationals Emiljano Marku, and Geg Gjegjaj, both aged 21, and 23-year-old Trandafilos Mhilli.
Six rooms on the first floor and two rooms on the floor above had been converted for the production of cannabis,” said Mr Evans. “This was a single crop; 297 plants, all in the same stage of growth and all 1.2 to 1.3 metres tall.”
Photographs showed the cannabis factory set-up. “These show fertiliser being used, significant re-wiring of electricity and all the usual accoutrements of a commercial cannabis farm,” said Mr Evans. “Lighting, timers, growing media etc.”
The estimated yield of the crop was between 8.3kg and 24.9kg with a potential street value of £83,000 and up to £250,000.