Probably this swis clock is one of the few left from those that RAF bought before war, it has the same housing as the Swiss Spitfire clock MK IIIA, bought also before the war, it has the same chronoflite movement Cal. Jaeger 330 signed Le Coultre.

Because it has a 24 Hr dial, is generaly accepted it was form a bombner as Lancaster, but i can not found a picture to probe it.