More than 50 vehicles were stopped in a crackdown on illegal traders in Northampton.
Trading standards officers issued 13 notices of intention to prosecute and HM Revenue and Customs fined a vehicle driver £500 for using red diesel.
Vehicle and Operator Services Agency (VOSA) officers issued 23 prohibitions for mechanical defects and three vehicles were taken off the road.
Environment Agency officers issued one caution during 10 waste carrier checks.
Police issued two fixed penalty notices for having no MoT and one for having no insurance.
Altogether 53 vehicles were stopped and checked during the operation.