Yep, the blue was used after a series of trials, to establish an effective camouflage colour for high altitude operations, particularly with RAF Germany, as the 'High Speed Silver' flashed and reflected in certain conditions, revealing location. The blue, also used on RAF and RAFG Sabres, was specially formulated for high-speed flight, and was used in conjunction with new, smoother, upper surface camouflage paints. The scheme, though, was relatively short lived.