By the time a team of police officers and engineers stormed a disused office block in Wigan, Greater Manchester, on a November morning last year, the building had been abandoned.
Left behind were rooms filled with thousands of cannabis plants: a nursery on the first floor, the growing crop on the second, and leaves drying out on the third. The criminal gang behind the marijuana farm is thought to have fled after the grid operator cut off the stolen electricity used to power scores of LED lamps.
