Crooks siphoned about £700 worth of diesel from the tank of a sleeping Polish lorry driver.
They got 500 litres after breaking through the faulty filler cap of his white Scania Elltrans lorry between 8pm on Wednesday and 11am on Thursday. It had been parked in the A41’s Bourne End service station.
Berkhamsted-based Sgt Peter Huffer said: “This is an unusual event, but clearly with the current price of fuel, it has become a valuable and desirable commodity.”