1939 Register

E.D. Letter Code CCYU
Borough, U.D. or R.D. Ilford
Registration District 191-2
Address 3 Special 1 Special 1, Redbridge, Essex
[This is the London County Council - Claybury Mental Hospital. See Wikipedia]

Schedule Surnames and Other Names O,V,S,P, or L M or F Birth S,M,W, or D Personal See Instructions
3/501 Knapp, Frederick C. Patient Male 1906 Single Incapacitated

NB - Staff and other patients not transcribed.

Source: findmypast - 1939 Register RG101/1108C/014/11