[Graham Boak]

The collector rings were not camouflaged because the paint would be burnt off by the heat. They are usually distinguishable in other photos. I've no explanation why this example appears different - perhaps it's new?

Later in the war some attempt was made to camouflage the collector rings, initially using black on night bombers but later a special white paint was used on coastal patrol and strike types. That's too late for Blenheims, however.