NOW IT CAN BE TOLD
Just released by the National Archives, this previously Top Secret image of the Mars (Mini Airborne Rations Shipper), retro-fitted to the bomb bay of the Vulcan for Operation Black Buck in 1982. There was concern that crew rations would pass their sell-by date during the lengthy sorties to the Falklands, so the Captain would despatch the Co-Pilot in the Mars to re-stock with suitable items at the nearest supermarket, hence the dual-purpose undercarriage quickly but cleverly designed in the days leading up to the operation by I. Hammer (Blacksmith) of Scampton village. (It is notable that the Hammer contract is the only Defence Contract to be completed within budget - "fifty quid - I only deal in cash, mate" - since 1849, and Lord Hammer of Scampton has thereby forged himself a place in history and now has many more irons in the fire).
The Co-Pilot would access the Mars using the door between the crew compartment and the bomb bay, the existence of which has only now been unclassified after more than fifty years of speculation since its inadvertent exposition in the film 'Thunderball'. It was only kept secret by carefully-managed propaganda promulgated by Vulcan aircrew who were under strict orders to describe any suggestion of such a hatch as being utterly vacuous.
In the event, the Mars was never actually deployed, due to the intrinsic inability of any crew to come to a mutual decision about whether or not they should purchase corned beef and Argentinian Tango.