'Knocker' is the nickname of the AEC 10 tonne Militant. It came in two varieties: Mk1 which looked really ancient (like a Matador), but with hand crafted ash frame cabs, and the MK3 which looked ancient - but with a little more chrome. Its role was as a heavy load carrier and was widely used in the RCT, RAOC and the RE. Some where equipped with CALM (Crane Atlas Lorry Mounted).
The Militant was designed in the late forties and entered service in the early fifties. It soldiered on in the Transport Regiments of the RASC, RCT and RLC until the early nineties. The last 'Knockers' left service in 2001 having been used as teaching vehicles in 166 Sup Regt RLC(V).
The Knocker had a top speed (optimistic) of 39 mph in both forward and reverse - up and down hill. This also made it difficult to use on the autobahns of Germany due to speed restrictions. It had no power steering and often required two drivers to turn the steering wheel and as a result RCT drivers were built like brick shit houses.
By the 1980s it spent much time on autobahn hard shoulders awaiting recovery. Frequently used by RE units to test M2 bridges, and to frighten the daylights out of drivers, fresh from basic at Leconfield, who'd trained on Ryder 7.5 tonners. The Knocker has been replaced in general service by DROPS.