When war broke out in September 1939, Triumph's entire stock of completed civilian machines was requisitioned by the War Office. The Coventry firm went on to develop a 350cc twin-cylinder model – the 3TW – specifically for military use, only for the destruction of its factory in an air raid in November 1940 to scupper the project. Installed in new premises at Meriden, Warwickshire, Triumph recommenced production of the single-cylinder sidevalve 3SW and overhead-valve 3HW models. The latter was based on the pre-war Tiger 80 sports roadster, the engine of which was modified to incorporate rocker boxes cast integrally with the cast-iron cylinder head, aluminium alloy being in short supply. Triumph's single-cylinder models were used mainly by the Royal Navy for despatch duties and general liaison, with the less-powerful 3SW reserved for the WRNS. Making it highly unusual to say the least, and possibly unique, this 3HW has been modified with a swinging-arm conversion, complete with friction dampers, giving it a distantly Italian look. The private vendor advises us that the machine was modified in the 1950s and has remained un-restored since then. It last ran in September 2019 and is described by the owner as running well. Accompanying documentation consists of copies of the motorcycle's Italian registration papers and Registro Storico Triumph entry.