Avro Arrow blueprints were saved by a draftsman in 1959 when John Diefenbaker, the Canadian Prime Minister, cancelled the project and ordered all the airframes scrapped and everything associated with the project to be destroyed.
https://www.cbc.ca/news/canada/saska...oyed-1.5416554
Ironically they are on display at the University of Saskatchewan's Diefenbaker Canada Centre. I would have thought the owner (the draftsman's son) could have found somewhere more appropriate to display them!