Chartered Accountant and auditor, he began his career with Griffin, Moscrop and Co. before joining Netherlands and Canada for Price Waterhouse from 1972 to 1976. On his return to the UK, he joined Neville Russell.
A partner in 1979, he was later named Senior Partner, a position which he held in Mazars UK until 2003. A member of the Mazars Group Executive Board from 1998 to 2006, he has notably played an important role in the firm’s development in the United States.
He is now a « senior adviser » of the Group Executive Board with responsibility for the international development, particularly in the Asia-Pacific region. Fellow of the ICAEW (Institute of Chartered Accountants in England and Wales), John Mellows is also the director of the charity organisation which promotes Christian standards in the arts.