They have been let by unsuspecting landlords and letting agents to well organised gangs of cannabis growers with links to major crime gangs.
By the time the police are involved, the property has typically suffered thousands of pounds of damage. Cannabis plants need heat and humidity to produce a good crop, so to help the hundreds of plants reach maturity fast, the growers rig up sophisticated hydroponic systems in every room of the house.
To provide the 24 hour water and lighting required, pipes, ducts and electric cables are run through holes drilled through your ceilings and heavy duty insulation fixed to the walls. Windows will be sealed up and the large amount of condensation resulting from the process will ruin whatever the growers have left intact.
To avoid arousing the suspicion of the electricity companies, growers also bypass the electric meter to tap straight into the main grid. Running huge amounts of unregulated electricity through a residential property system is highly dangerous and can result in fires and sometimes police find electrical booby traps attached to entrance points which can deliver enough power to kill a person.
Much more rarely, gangs may use a house to produce other drugs in powder or tablet form, or use it as a "safe house" to prepare, bag and store drugs for sale.
In the meantime, if you're letting your house follow these simple tips.
Before you let
- Meet the prospective tenants and be aware growers often send apparently respectable couples to meet the landlord as a cover. Later they will disappear without trace. Make sure you get photo ID from these people, check previous references and go round a couple of weeks after they've moved in to make sure they are genuinely living there.
- Be very suspicious if you are offered six months rent up front in cash
- Make sure your property has outside lighting; and cut back overhanging or high vegetation which will discourage growers as they like their activities to be hidden
After you let
- Keep your neighbours informed and get them to report anything suspicious to you or your letting agent.
- Visit the property regularly, or ensure your letting agent is doing so. Excuses from tenants or agents as to why this is not possible should arouse your suspicion.
- Check the loft too
Look out for
- Windows always closed in summer and curtains are permanently drawn
- Excessive condensation at windows
- Pungent or chemical smells
- Large amounts of compost, plant pots, chemicals or fertiliser (or empty containers) stored
- Neighbours reporting many frequent different visitors to the property OR no apparent movement of tenants at all
- Excessive security measures added to property such as bars at the windows or reinforced doors
- Lookouts - usually young/teenagers hanging about outside to warn the users of potential trouble
If you suspect anything
Call the police as soon as you can. If you live near a rental property and you notice any of these signs you can call the police too. Just get in touch with your local police station.