Hassan was born in London where his father, of Northern Irish descent, owned a clothes store in Holloway.
[1] After it was put into liquidation and taken over by Rolls-Royce at the end of 1931 Hassan left Bentley Motors and worked for Barnato.
[1] The vast majority of prewar ERAs are still in existence and they have continuous and verifiable provenance.
At the end of the war he returned to Coventry to continue to work with Bill Heynes on what became the XK engine.
In 1950 Hassan joined Harry Mundy at Coventry Climax, and they designed the FW series (featherweight) lightweight overhead camshaft engine intended for fire pumps but further developed for motor racing.
[3] In later years, Le Mans-winning Jaguars were powered with a modified V12 racing engine.
He retired on 28 April 1972 at the age of 67[2] and was awarded the OBE for his services to motor sport.
After Ethel's death he lived with his son, Bill, at Kenilworth though he later moved to the Motor Industries Benevolent Home and died at Easenhall, Warwickshire, on 12 July 1996 aged, 91 years old.