Re: azure blue over white pru spitfire?
 

My take on it is that it was grey or blue over standard white for low level ops over sea. Difficult/impossible to discover from the surface, good camuflage from above...

K

Re: azure blue over white pru spitfire?
 

Except that a single-engine fighter is not a suitable machine for maritime recce, as such.

However, as most of the desert war was fought along a narrow strip of coastal land, perhaps they were used for low-level PR visits to the important supply harbours, with the cruise out and back being out to sea? It is a shame we don't have any accounts of North African PR work.

Re: azure blue over white pru spitfire?
 

this might seem like an irrelevant observation, but shouldn't it be equipped with a tropical filter then?

Re: azure blue over white pru spitfire?
 

The particular aircraft that started this discussion was not an Middle East machine, as mentioned above, hence no filter. However, the scheme, or something very similar, was seen on other ME aircraft. As you suggest, even the PR Spits seem to have kept the tropical filter for ME use.