He read mathematics at Lincoln College, Oxford, gaining a BA in 1981 and D.Phil.
He later studied at International Institute for Management Development (IMD) in Lausanne in 1988.
In August 2001 he became managing director of Energy Trading, replacing Nick Horler.
It was announced in September 2011 that he would become chief executive of E.ON UK, taking that role in January 2012.
[citation needed] Tony was appointed chairman and non-executive director on 1 August 2017, having retired from E.ON in July 2017.