A raid at a former Kettering bingo hall found a full house of mature cannabis plants.
There was a knock at the door at Gala Bingo in High Street at about 10.30am this morning (Friday) after intelligence that a second cannabis factory in four months was inside.
Thermal imaging had shown the building to be warm despite being supposedly not in use with officers smelling cannabis as they walked past.
Shoppers watched on as 25 officers and dog units surrounded the venue - right under the noses of town centre visitors - before breaking down the rear doors.
Once inside officers hit the jackpot.
READ MORE: Kettering cannabis factory in pictures
They found two rooms full of plants covering all four corners of the property.
Plants of the class B drug were just weeks away from being harvested and distributed with a "sophisticated" hydroponics set-up.
Police have since confirmed more than 2,000 plants were found. Over a year these plants would yield drugs with a street value of £2.8m
PC Colin Gray, from the force's proactive team, said: "This is a significant find that will disrupt organised crime groups and the distribution of cannabis locally and further afield.
"It is one of the largest I have seen even when compared to a site we found in Corby earlier this year."
Those behind the operation had spent thousands boarding up the bingo hall and putting fencing at the rear.
Nobody was inside the cannabis factory but the bingo hall's kitchen had been in use.
The plants were coming of age and only about three weeks away from harvest and distribution. Those behind it were almost there in their bid to illegally make hundreds of thousands of pounds.
PC Gray said: "These crime groups blight society by manufacturing and selling controlled drugs in Northamptonshire.
"We will never stop trying to bring them down and this type of activity will continue."
Neighbours said they had smelt cannabis in recent months.
A previous factory was found inside in February and is under investigation. The bingo hall shut last year and has since been leased.
Officers will be at the bingo hall for most of the day removing the plants.