Detectives have discovered what might be the largest illicit cannabis grow op in UK history. The illegal cultivation site was found in a series of abandoned mines that stretches for 10 acres underground.

Since discovering the illegal grow op at the end of September, UK police have confiscated an estimated £1,000,000 ($1,312,000 USD) worth of cannabis from the underground site, which is near the small, unassuming town of Bradford-on-Avon, Wiltshire. The caves form part of the former Bethel Lime Quarry.

Authorities "are not sure how vast the production site is because there are ­significant safety issues" preventing them from fully excavating the area, according to police, who told Daily Mail that the investigation would take at least a week to finish based on the sheer size and treacherousness of the caves.

So far, police have found 4,425 plants across 20 rooms in the caves, and three men have been arrested in connection to the case. Two of therm—Alksander Shyti, 45 and Altin Deda, 39—have been charged with illegally growing cannabis.

Mining ceased at the quarry at the end of the 1800s and the caves went on to serve several other purposes since then. The government used them, to store naval equipment during the second World War and it was later operated as a mushroom farm by Heinz soup until 2010. At some point after that, the illegal growers decided to transform the quarry into the ultimate man-cave.

As new details emerge, we hope the authorities notify Simon Pegg and Edgar Wright as the case has all the makings for a follow-up to 'Hot Fuzz.'