MB BChir Cambridge 1943, MA 1948, MD 1955; MRCP Lond 1949, FRCP 1970; DCH 1951.
Forrester studied at Cambridge and Manchester Universities. After qualifying in 1943 he was house physician at Withington Hospital Manchester before joining the RAMC. In 1947 Forrester returned to Manchester and held resident positions at Withington Hospital and MRI before joining the staff of the Royal Manchester Children's Hospital. In 1952, he worked as temporary registrar in the neonatal department of St Mary's Hospital Manchester. Later that year Forrester was appointed senior registrar in paediatrics for Royal Manchester Children's Hospital and St Mary's Hospitals and was lecturer in child health at the University of Manchester. Forrester later became consultant paediatrician for Wigan and Leigh Hospital Group and the Royal National Institute for the Blind.