Families are being urged to be vigilant of rogue traders following reports of elderly people being targeted by doorstep callers.

Staffordshire County Council's Trading Standards service has received reports of elderly residents being approached and told they need work carried out on their property.

Now the authority is reminding all residents to research traders before agreeing to work, while Staffordshire Police is calling on people to report incidents where they have been left feeling threatened or intimidated.

In a recent case a resident in their seventies was initially told by a trader they needed a leaking chimney fixed for the sum of £400. However the job soon escalated to the replacement of the entire roof at a cost of £18,000. The resident stopped the worker after they had begun to immediately remove roof tiles and expose the wooden structure.

Rogue traders typically target older people for home repairs; mainly roofing and guttering work. They start off by saying there is some work needing to be done to the house (the gutters need cleaning or that they can fix a small leak for example), and saying if the work is not done, it will be a very big job to put right. The prices charged are excessive and they rarely provide paperwork so they can't be traced once they've left people's homes.

Often the work they suggest doesn't even need doing and if it is done is done to a poor standard.

Victoria Wilson, cabinet member responsible for Trading Standards at Staffordshire County Council said: "This type of criminal activity that usually targets older more vulnerable residents is particularly cruel. Not only can it leave people quite shaken up but can also leave them seriously out of pocket.

"Our Trading Standards service have had a few reports recently of doorstep criminals and we're reminding residents to be vigilant and to report any incidents.

"Reputable builders, roofers and gardeners do not usually cold call. People needing work done on their homes should always get three quotes for the work, never pay up front and should not pay by cash. And, if anyone is unsure about the caller, they should ask them to make an appointment to come back when a friend or family member can be with them. Homeowners are also reminded to be vigilant as to which online trader matching and referral services, they leave their details on."

Superintendent Tom Chisholm, head of neighbourhood policing at Staffordshire Police, said: "Nobody should feel threatened or intimidated in their own home and anyone who is made to feel this way by the actions of someone claiming to be providing a service should contact the force.

"Previously there have been incidents where someone claiming to be a trader will knock on the resident's door and tell them their property is in need of work – which is not normally the case. If the work goes ahead it is often of low quality and the injured party is over charged.

"Victims tend to be older and feel pressured into agreeing to the work. There have been occasions where they have been escorted to a bank to withdraw money.

"Sometimes these rogue traders are associated with wider criminal gangs and it is important that people report their concerns."

Trading Standards officers are now warning householders to be aware and never:

• Agree for work on their house or garden by someone who knocks at their door uninvited

• Give money to or sign any forms for people who turn up on their doorstep

• Open the door to strangers or allow uninvited callers into their home

• Let somebody take them to the bank to take money out

Anyone who feels afraid or threatened by a doorstep caller should call 999. For non-urgent calls they should contact Staffordshire Police on 101.

People can get further advice by calling Consumer Direct on 0808 223 1133 or the county council's Trading Standards team on 0300 111 8000.