Info U.K. CAA 2006 (JAR)
https://publicapps.caa.co.uk/docs/33/CAP698.pdf
CAA JAR-FCL Examinations Aeroplane Performance Manual
Engine out perf may have orrigionated from ICAO obstacle clearance studies?
P.S. The paper ‘Analysis if takeoff performance’ 1967 refers to BCAR. There may be other refs of interest.
http://naca.central.cranfield.ac.uk/...rc/cp/1034.pdf
References (#2) British Civil Aircraft Requirements 1966 section D