The role of motorcycles in the Army has not changed significantly since their invention.  They are used by RLC Postal and Courier despatch riders to deliver mail and documents around the battlefield and particularly between headquarters.  They escort convoys and abnormal loads, and guide vehicle packets into locations.  They are used for reconnaissance ('recce') as their small footprint gives them easy access to most locations and makes them easy to conceal. 

The RLC Museum has one of the 3 diesel motorcycle prototypes trialled by the MOD recently.  However the machines were found to be heavy and slightly unwieldy, despite their copious torque.  It was felt that diesel technology needed to advance more before the British Forces would consider using it in a motorcycle.