Guy became Chief Executive of the Advertising Standards Authority, the regulator of UK ads in all media, in 2009. He is responsible for executing the ASA's strategy to make ads responsible, including through the development of regulatory policy, the provision of CAP advice and training, the investigation of complaints, proactive project work, enforcement activity and the system's communications, marketing, public affairs and research activities.
From 2013 to 2016, Guy chaired the European Advertising Standards Alliance, the single authoritative voice on advertising self-regulation comprising national advertising self-regulatory organisations and organisations representing the advertising and media industries in Europe and beyond. He remains a Board and Executive Committee member.
Guy is a member of the government's Cosmetic Interventions Advisory Board, a member of the new Fundraising Regulator's Standards Committee, a member of the government's Consumer Protection Partnership Strategic Group, a member of the International Chamber of Commerce's UK Marketing and Advertising Committee and a Fellow of the Institute of Promotional Marketing.
Married with three children, he lives in North London.