Police seized 23 cannabis plants with a street value of around £6,900 in a raid on a property on Nether Hall Road.
The raid took place in a flat above the Sweet Bakery store, at about 6pm on Tuesday.
A neighbouring businessman, who asked not to be named, said: “I saw the police go in – there were a few of them.
“They told me they found cannabis, and that they had been looking for a factory around here for some time.”
Ali Hassan, who works in a barber’s shop next door to the bakery, said: “My mate told me yesterday that he could smell drugs, but we thought it must have been someone walking past smoking it.
“I hadn’t noticed a smell at all – it’s a shock to discover there was a factory right next door.”
A police spokeswoman said: “We attended and discovered a cannabis set-up, and 23 plants were seized.”
No-one was arrested.