Making your farm thief-proof can be pretty difficult. You can put a gate across the driveway and string up PIR-activated cameras or alarms on the barns, of course, but the very nature of most farms means there are often plenty of ways in which one of our light-fingered friends can sneak into the farmyard.

But technology, as ever, is coming to farmers’ aid. High-tech Berkshire firm Optex Europe is finding a good market among farmers wanting to know who comes on to the farm. It markets a system called Smartline that uses one or more pinpoint-accurate infrared beams that can stretch across a 200m (if hard-wired) or 100m (if wireless) distance in any one stretch. So you can virtually ring-fence the farmyard and farmhouse.

You can go for the basic system with a single beam, or a more advanced one with several beams up to 3m in height. The beams are not visible to the human eye (even at night), so the intruder won’t know he has broken them. Equally, the system can be set up to ignore birds, rabbits or other animals innocently breaking the beam.

The towers that contain the infrared projectors can be attached to a building or fence, or they can be installed in free-standing fashion across a field or area of hard-standing.

If away from buildings and mains power, the towers can be battery powered. The batteries last from four to 10 years, says Optex, depending on how many batteries you fit. The company is also trialling a solar-powered version to extend the battery life of the equipment.

The equipment can be self-installed by a farmer or fitted by Optex’s network of installers. It is designed to be compatible with most types of alarm or CCTV system; equally it can be expanded to cover several sensitive areas (such as the fuel store and the workshop, for instance) at the same time.

Starting cost for two towers for a farmer fitting it himself is £525.

Read more: High tech route to farm security