The change of design strategy from Safe Life to Fail Safe is the other probable reason for the reduction in fatalities that reach a peak in '52 '53. at 330+ fatalities, which fell to 42 deaths in 1960. The Americans were the first to see the problem with Safe - Life because it could not guarantee safety in a catastrophic failure. All U.K A/c designed after '56 are 'Fail Safe' See this article from '56 which is a report about a talk given to RAeS by a chief engineer from Lockheed, he delivers a 'coup de grace' to the Safe Life strategy
1956 | 0396 | Flight Archive 1956 | 0397 | Flight Archive 1956 | 0398 | Flight Archive 1956 | 0399 | Flight Archive The Valiant was Safe Life with an airframe made from DTD683 which could and did fail catestrophically as in
XD864 and probably a few others. The Shackleton and Argosy were two others that were potentially compromised in this way, but they unlike the Valiant were redesigned and rebuilt to fail safe. I have no information about what happened to the Meteor, but it would have been designed to safe-life.