Officers also uncovered beds with mattresses, duvets and pillow cases along with food provisions, including a box of tomatoes.
Image copyrightWEST MIDLANDS POLICE/PA WIREImage captionPolice had to get through an internal steel-barred door, reinforced with a metal grille, and an industrial-sized padlock
Det Insp Jim Church said: “This is a sophisticated, organised crime operation that has clearly been running for some time, but which we’ve now been able to dismantle.
“We’ll be working to establish the full scale of it and make the property safe.”
Cllr Majid Mahmood, who represents the ward, said: “Questions need to be asked about how those people were so brazen, living there and running a cannabis farm, when you’ve got shops nearby and a church, so you’ve got a lot of footfall.
“I think a lot of people might have thought they were the [demolition] contractors, coming and going, but with the stench of the plants that must have been coming from there, I’d have thought someone would have noticed.”
Image copyrightWEST MIDLANDS POLICE/PA WIREImage captionLiving quarters were also found within the cannabis factory