Sir Brian was injured in the killing by the IRA of the British Ambassador to Ireland, Christopher Ewart-Biggs, in 1976. The car in which the party was travelling was hit by a bomb concealed in a culvert under the road. Sir Brian's Private Secretary, Judith Cooke was also killed, and the driver, Brian O'Driscoll, was also injured.
Cubbon co-founded intelligence business consultancy Hakluyt & Company Ltd, in 1995 with several other former secret service officials.
- Press Complaints Commission Commissioner, 1995-2002
- Member of the Charter Compliance Panel of the Press Complaints Commission 2004-