Landlords need to protect themselves against the tactics of criminal gangs, according to the National Landlords Association (NLA).

It warns that privately-rented homes across the UK are being used as a smokescreen to grow cannabis in homemade ‘factories’, and produce the drug crystal meth.

Prostitution is also found across the private-rented sector, with homes being used as brothels. Criminals are attracted to rented properties, often in quiet residential areas, as a base to operate without the fear of being disturbed.

However, it’s the landlord who ends up footing the bill. Many insurance policies are rendered invalid when criminal activity takes place in a property and the damage caused can run into thousands of pounds.

One NLA member lost £20,000 when two of his properties were used to grow cannabis. The gang involved took out internal walls and rewired the property directly to the electrical mains. And landlords who find brothels in their properties and fail to report them can face prosecution.

The NLA recommends that landlords take detailed references. These should include a credit check, and references from their employer and their current landlord.

It also warns not to take rent up front, as criminals offer this as way to ensure they are left alone. For the same reasons, check on the property regularly. This can be done at least quarterly and more regularly if you have concerns, provided you have given sufficient notice.

The NLA also suggests to get to know the neighbours, as they can alert you to any suspicious activity. If you have suspicions of criminal behaviour do not confront your tenant. Go straight to the police.

David Salusbury, chairman of the NLA, said: “It is vital landlords are aware of the threat these criminals pose. Criminal activity not only has an impact on the landlord’s property