Police finding 20 cannabis farms a day

Police discovered more than 20 cannabis farms and factories every day last year as they seized drugs which could sell for £100m on the streets, new figures show.

Senior police chiefs said the size and scale of the farms were getting smaller as criminals producing the drug were spreading the risk and minimising potential losses by employing a large number of so-called gardeners to manage small sites across multiple residential areas.

A total of 7,865 farms were found across the UK in 2011-12, up 15 per cent from 6,866 in 2009-10 and more than a 150 per cent increase from the 3,032 identified four years ago, a study by the Association of Chief Police Officers (Acpo) found.

There has been a "move back to the use of residential property" and dismantling factories was seen as "a short-term solution, with missed opportunities for further investigation into potentially linked factories", the police chiefs said.

The number of offences related to cannabis production is also increasing, from 14,982 cases in 2010-11 to 16,464 last year.