William (Bill) Marmion was the deputy leader of the opposition in Western Australia until November 2020. He was elected to the position in June 2019, following the resignation of Dr Mike Nahan and the election of Liza Harvey as leader.
Mr Marmion was the Liberal Party Member of the Western Australia Legislative Assembly for Nedlands from 2008 to 2021. He served as a minister in the government of Colin Barnett from 2010 to 2017 where he held portfolios in transport, innovation, state development, finance, mines and petroleum, water, environment, housing, science and innovation, and commerce.
Prior to entering politics, Mr Marmion was a civil engineer for Main Roads Western Australia, a VFM auditor for the state government's auditor-general, and had his own strategic planning business. He was also president of the state branch of Engineers Australia for three years.