Sleaford area police are issuing advice to farmers to make it harder for thieves to steal machinery from farmyards.
The message is being issued to all Lincolnshire farmers and rural industries.
PC Martin Green of Sleaford Police said: “Lincolnshire Police are receiving reports of thefts of vehicles from farm yards, more often than not by use of the keys left in the vehicle.
“This is a reminder to remove all keys and valuables from vehicles. Some insurance companies won’t accept any claims if keys are left In the vehicles/cabs.
“Don’t make it easy for them, lock it or lose it.”