A housing association is warning tenants to be on their guard after a rise in bogus callers.
Thrive Homes, based in Croxley Green Business Park, owns and manages more than 4,000 rented and leasehold properties in Hertfordshire and Buckinghamshire.
The housing association has reported a spike in the number of complaints they are getting from residents who have been visited from people posing as Thrive Homes staff.
Neil Davis, customer service manager at Thrive Homes, said that if contractors were doing work at Thrive properties, the tenant will be told in advance.
He said: "Incidents of bogus callers seem to happen in spates so, at one point, we were receiving several calls a day but currently we get perhaps one call a week."
"These are often false alarms which turn out to be genuine people, such as contractors calling in advance to fix appointments.
"But, worryingly, we sometimes get calls from tenants after they have let someone in but want to check the caller was genuine."
Mr Davis is urging people not to let anyone in if they are unsure who they are.
Staff from Thrive Homes will always carry identification, with a photograph, and all its contractors will carry identification and a letter of authority from the housing association.
Mr Davis said that: "If we are sure the callers are unrelated to work we are doing, we recommend the tenant calls the police non-emergency number and we contact the neighbourhood police teams to make them aware."
He added: "Anyone who gets a doorstep caller claiming to be from Thrive Homes should ask to see the person’s ID. A genuine member of our staff will be more than happy to show you their identification.
"Then you should check the ID and, if you are still unsure about the person, ring us on 0800 917 6077. Don’t let anyone into your home if you are uncertain about them."
Residents are advised not to let anyone in who they are unsure of, but instead ask them to come back at a more convenient time when they are not alone.