Block Stem security system is suitable for tractors, handlers or any other machine with exposed power steering rams. Imported from Italy, it costs £240 and is available with a five-year warranty in case of any failure.

It has full Thatcham accreditation, and Richard Baxter from importer Derwent Trading International (01902 744 475) says he is seeking approval from the NFU Mutual to for it to qualify the system for discounts on insurance premiums.

Manufactured in two sections from heavy-duty steel, the tamper-proof unit slots together over the hydraulic steering axle ram of any self-propelled machine, and is locked in place with a unique key when the wheels are at full lock.

Once fitted, the unit not only acts as an effective visual deterrent. It also means the vehicle can only go round in circles, thus preventing the vehicle from being loaded or driven away, even if the thief has the ignition key.

Block Stem is available in different lengths up to 220mm and diameters from 22mm to 50mm.