Air-Drive Harrier backhoe.

The Harrier was developed by Air-Drive Limited in late 1970 and early 1971 as, in effect, a mini-digger on a road-legal 4x4. McConnel's PA44 Power Arm — a small hydraulic backhoe already sold for mounting on tractors and barges — was fitted to the rear of a heavily strengthened Series IIA 109" chassis, with a French-made Montabert hand-held hydraulic concrete breaker carried at the front. Two hydraulic pumps were driven from the gearbox, an eight-blade fan and oil cooler handled the extra heat load, and two deployable outriggers steadied the vehicle while digging; a bank of power take-off levers controlled the hydraulics. Air-Drive aimed the package at light road-repair contractors and local authorities who wanted one compact vehicle instead of a lorry plus excavator.

Commercially the Harrier could not carve out a market from beneath the all-dominant JCB, and only around ten were built. The surviving prototype and company demonstrator, WPP 101J (chassis 27706819G, 2.25-litre diesel), featured in Air-Drive's brochure and was the vehicle tested by Rover for type approval. Only it and one other unrestored example are known to survive. WPP 101J was comprehensively restored by Rob Maude in 2016, remains fully operational, appeared at the 2018 Goodwood Festival of Speed, and is now part of the Land Rover Heritage Collection.