By The British Engraving & Nameplate Mfg. Co. London W.1. Large cream coloured plastic/acetate protractor. Approx. 30cm wide x 15cm top to bottom. Wooden handle/grip. Marked with Air Ministry and King's Crown. Some of the lines and numbers have partially worn away and the protractor is somewhat warped, not sitting flat on a level surface (see last photo.) It might be possible to apply gentle heat and restore the shape, then cooling whilst keeping flat. Used to plot routes, bearings etc. We have only had a handful of these in the last 20 years and they are really quite difficult to obtain. Stock code M18573.