Nearly 400 cannabis plants have been seized by police from a house in Wickford in Essex.
Police officers raided the property at around 3pm yesterday.
Officers found an outbuilding with three purpose built rooms, with fans and hydroponics, full of cannabis plants.
A firearm was also found and seized along with the drugs.
A 56-year-old man from Wickford was arrested on suspicion of cultivation of cannabis with the intent to supply and is still being questioned in custody this morning (May 30).
Sgt Dave Darnell, of Essex Police, said: "I am pleased that a large quantity of drugs has been seized and will no longer be hitting the streets of this area.
"Where we receive good information from the community about who they suspect may be committing crime in their area, we will act. I urge you if you know who is involved in drugs to contact us immediately so we can take robust action.”