A series of photographs from World War 2 reveal that the lake at Blenheim Palace was used to test landing craft in the run up to D Day. The estate was a temporary headquarters for MI5 after its London base was bombed in 1940. It is thought Blenheim was chosen for the trials because of its proximity to the Churchill family home and the Morris motor works in Oxford where the vehicles were built.
They were tested as part of Operation Neptune, a British initiative to develop its own landing craft.
The photos featured in the palace’s online celebrations for VE Day, however, this page has now been removed.
More information can be found at their website