NavList:

I tend to disagree with David Pike: the table top models were used in EVERY RAF airplane carrying a dedicated navigator, including the Lancaster which was the most widely used British bomber during WWII. The Mk. IIIH was the last of the line, meaning it would not have been used in the medium bombers (Hampden, Wellington) that were in use at the start of WWII. Therefore, I think there is a real chance that this one was used on board  a Lancaster. If nothing else, at least these were standard on all operational Lancaster flights. Of course, this particular specimen could have been used in aircraft like the Liberator or Sunderland, but there were much fewer of these than there were Lancasters.

Ronald van Riet