LETTING agents too often lack key knowledge about properties, according to an investigation by Which?

The consumer body says some agents are showing potential tenants around damp properties and not informing them of important safety details during viewings.

Which? sent undercover researchers on 30 property viewings in England and Scotland and provided them with a list of questions to ask the letting agent, designed to uncover whether they were giving vital information.

Viewings took place in Manchester, Leeds, Bristol, Edinburgh and London. Which? said one-fifth (20 per cent) of properties visited had issues with damp.

It also said that on several occasions letting agents "brushed off" questions about maintenance, with some stating work would be carried out before the tenant moved in, or would need to be dealt with by the landlord.

Property expert Kate Faulkner told Which? that tenants should avoid this type of verbal agreement and, instead, repairs should be made conditional as a special clause in the tenancy agreement.

Which? also said researchers reported feeling pressured or rushed into making a decision by agents.

It said two prospective tenants were asked by agents to hand over upwards of £1,000 and commit to living in a property despite not being able to view all its rooms.

The results also highlighted concerns over the standard of safety information.

Half of agents were unable to provide any information on the property's boiler, and just one in three were rated good for their knowledge of carbon monoxide alarms.

The findings were released in the same week the Government proposed longer tenancies to give renters more security. A minimum three-year contract is being consulted on to stop landlords forcing tenants out at short notice.

Chris Norris, director of policy and practice at the National Landlords Association, said: "All tenants should be able to expect clear, accurate answers when viewing a potential home and shouldn't be afraid to ask questions.

"There is no excuse for an agent to not be up-to-date with current legislation, especially regarding safety."