Copy of a letter from WSC to President [Roosevelt] referring to a late night discussion on the importance of co-operation between UK and US "cipher people". He says that although naval ciphers are frankly discussed between the two Intelligence Services, the UK appears to lack information about the US diplomatic and military ciphers and that he had ordered intelligence work on US ciphers to cease once the two countries became allies. He asks the President to handle the issue personally and ideally to burn his letter. Unsigned carbon typescript annotated [by Denis Kelly] "'42 Archives".