After Oxford University, Vernon worked at Accenture from 1969 to 2010 and became International Chairman in 2001. From 2010 to 2016 he was Chair of the British Council where he led the organisation through considerable change and expansion.  He is currently on the Board of FTI Consulting Inc and chairs the Boards of Martin Randall Travel, One Medical Group and the National Opera Studio.

For many years, Vernon has had a deep involvement with music. He was Chairman of English National Opera from 2006-2012 and is now President.  He now also chairs the Leeds International Piano Competition and the Britten-Pears Foundation. For many years he held around 80 concerts a year at his Kensington home.

He was knighted for services to Music in 2011. He is a Fellow of the Royal College of Music and an Honorary Fellow of Trinity Laban. He received the 2013 Association of British Orchestras Award.