Leicestershire Police have issued a warning to van owners.
Officers are reminding van owners to make sure their belongings are secure at all times.
This follows a string of thefts from vans across the area in which tools have been stolen from vehicles parked at residential addresses.
In November there were 68 thefts compared to 49 in October, with another 25 during the first two weeks in December.
Detective Chief Inspector Mark Sinski, from the Force Intelligence Bureau, said: “It takes seconds to steal a vehicle or tools inside which can be worth thousands of pounds. Never leave your keys in the ignition or the doors unlocked while you’re away because replacing these items can be costly and the business is lost substantially.
“There are steps van owners can take to help prevent themselves from becoming victims of this crime. We would always advise security to mark any tools. If in the unfortunate event they are stolen this will make them much easier to trace. When possible, remove all valuables from your vehicle.
Officers want van owners to make sure that their vehicle is locked at all times, even when leaving it for less than a minute and if possible park in a well-lit place to deter potential thieves.