[Graham Boak]

I presume you doubt the use of Sky Blue in the Mediterranean, rather than its existence. Evidence for the latter can be found in many places, not least on relics from the BoB – though there were no Air Ministry Orders covering its use. It has been recorded on the undersides of aircraft delivered to Australia (Pentland), described on Spitfires destined for the Mediterranean (Barbic), and recorded (by noted artist Ron Belling) on the undersides of earlier aircraft in South Africa. No AMOs cover those, either. I’m afraid that the AMOs do not provide a fully comprehensive description of camouflage on overseas aircraft. (Or, arguably, home-based ones either.)

It appears to be accepted that ME Command rejected the use of Sky as too light – presumably they first saw it on Blenheims. This particular despatch has not been published, to my knowledge, but many sources (e.g. Huntley) either refer to it or act as if it existed. Actual documentation on any particular colour on ME undersides appears to be thin, at best. So Sky can be ruled out, or at least discounted. Given that a light blue colour is mentioned, what could it be if not Sky Blue? It may have been the very similar Azure Blue, although I think that the date of introduction of this colour would rule it out for at least the 1940 deliveries. Even so, this is but another hypothesis, with perhaps even less in its favour. If not Sky Blue, then what?

There has been considerable confusion over the various underside options. Sky Blue (1930), Sky Blue (RAE), Sky, Azure (another 1930 colour), Azure Blue, Light Mediterranean Blue, duck egg blue, duck egg green, etc. Until recent research proved otherwise, anecdotal evidence for other colours than Sky in the Battle of Britain was regularly dismissed. It was Sky or, well, Sky. That Sky Blue was widely used on undersurfaces of RAF aircraft in tropical areas is only a suggestion (or, if you like, a hypothesis). It cannot be otherwise, given the level of evidence. Occam’s Razor suggests we adopt the simplest solution that best describes the situation: to my mind this means Sky Blue. This does not mean that every, or even any particular, Hurricane on Malta had this colour. It does suggest that Sky Blue is the likeliest colour, at least for the later 1940 deliveries.

We do need more, and harder, evidence. Or at least CJE does.