Barnes Wallis's design of the 'Victory' bomber wasn't built as understand it, because Wallis wanted to devote its use to one big bomb! Whereas the Air Staff couldn't accept an aircraft so specialized.
Later, the Lancaster was found to be able to accommodate the grand slam and tallboy bombs. The point being that a 'Victory' bomber wouldn't be able to carry smaller bombs, i.e. it wouldn't have been designed built with the fixtures and fittings to hold a multiple bomb load.