FT941-10378 _AN-EBJCNAABFT 940210 FT 10 FEB 94 / World News in Brief: Policeman stabbed to death Police sergeant Derek Robertson, 39, was stabbed to death as he fought three masked raiders at a sub-post office in Croydon, south-east London. Countries:- GBZ United Kingdom, EC. Industries:- P9229 Public Order and Safety, NEC. Types:- NEWS General News. The Financial Times London Page 1