The number of cannabis farms uncovered by West Mercia Police has more than doubled in less than two years.

The force, which covers Shropshire, Herefordshire and Worcestershire, have raided 46 since 2009, the study by Association of Chief Police Officers (Acpo) found.

Across the UK, the number of cannabis factories found by police totalled 6,886.

It was more than double the 3,032 found in the UK two years ago.

West Yorkshire topped the list for the highest number of cannabis factories found in a police force area.

Between 2009/10, 896 cannabis "farms" were found in the region.

Commander Allan Gibson, the Acpo lead on cannabis, said the findings came as no surprise and the rise was in part down to an increased focus on the issue by authorities.