Police are urging neighbours to keep an eye out for cannabis factories on their doorstep.

Bradford District Drugs Team say these factories are elaborate operations and are not something which can be set up without arousing suspicions of people living and working in the area.

Clues that could give such factories away include lots of banging as factories are set, people seen coming and going with bags of fertiliser and compost and powerful lights.

Curtains are likely to be kept closed at all times but bright lights will be left on around the clock. When the crop is harvested, bags might be spotted being loaded into vehicles.

Landlords are also being asked to keep a watchful eye on property and tenants.

Anyone with suspicions should call Dob in a Dealer on 0800 555 111.