Tongue (Sheet 10) 1950.
After the Dunkirk Evacuation in May 1940, the threat of invasion to Great Britain looked likely, but when the British military looked at the existing Ordnance Survey maps, they found they were not up to the job. Ordnance Survey immediately began an intensive programme of updating the military’s sheets and the first new maps for England and Wales were issued in the summer of 1940 with maps for Scotland (considered less likely to be invaded) in 1941. The purple inked Cassini grid references were unique to the military maps - they were designed to look like normal Ordnance Survey grid references, but they did not make sense when related to the National Grid. The code to interpret this military ‘purple grid’ was top secret during WWII.
This map has been stored folded and will need to be mounted onto a board for framing. However the colours are strong and the condition is good with no tears or holes. See seller’s profile for full range of maps available.