More than 70 vehicles were stopped across Derbyshire on Wednesday as part of a crackdown on potential rogue traders.
The day of action took place as part of a national week of activities.
Roving patrols were carried out throughout the county, with officers attending reports of suspicious activity and a checkpoint was also set up at Tibshelf services, to target vehicles as they passed through the area.
The county teams also spoke to a number of residents who had contacted police with information about suspicious activity, giving advice on rogue traders and how to avoid becoming a victim of doorstep crime.
PC Chris Bond, from the intelligence unit at Derbyshire police, coordinated the action day. He said: “Rogue traders are people who will use fraud to try to con vulnerable people into paying for unnecessary or vastly overpriced work to their home.
“The aim of the operation was to target possible rogue traders and act as a reminder to those who try to con the most vulnerable in our communities.
“We had a successful day, with many agencies working together to also educate traders and we will be continuing to work with partners over the coming months.”
Joining police at the motorway checkpoint was HMRC, who carried out fuel dip testing, the Department for Work and Pensions and VOSA, which made sure that vehicles were safe to be on the roads.
The Environment Agency were also on hand to give advice to traders on the materials they were carrying, and the officers are working further with a firm who were found to be transporting loose asbestos inside a van.
73 vehicles were stopped in total, 33 passed through the motorway check point.
Four vehicles were seized because they were uninsured and two drivers were fined £500 each after they were found to be running their vehicles on red diesel.
VOSA issued four immediate prohibition notices to vehicles too dangerous to be on the road.
There were also a total of eight trading standards offences across the county and in addition the Department for Work and Pensions are carrying out further enquiries into six people believed to be working while claiming benefits.
Robert Taylour, head of Trading Standards at Derbyshire County Council, said: “Our officers joined mobile police units as part of our on-going work to crackdown on rogue traders.
“Most of the offences we found related to paperwork which did not comply with a customer’s legal right to a seven day cooling off period when signing a contract for goods in their own home.
“There was also evidence that some companies were not giving full details to customers, something which is common place with rogue traders who do not want to be traced.
“In Derbyshire there is absolutely no need for anyone to leave themselves open to rogue traders by using doorstep callers. Our Trusted Trader register has over 1,350 traders who promise to do a good job at a fair price and promise never to cold call.
Anyone concerned about suspicious callers in their area should call Derbyshire police, on 101, or dial 999 if a crime is in progress.
To find a Trusted Trader visit www.derbyshire.gov.uk/tt or call 08456 058 058
People can also report a rogue trader and get advice through the Citizens Advice Consumer Service on 08454 040506.