Based in Sheffield, Baker worked as a freelance writer and became active in the Green Party of England and Wales. He served as co-chair of the party in 1990–1991, and also as a speaker for the party. He co-wrote the party's document The Green Budget, published in 1991.
At the 1992 UK general election, Baker stood in Sheffield Hallam; he took less than 1% of the vote, and was not elected. During this period, he became the leading opponent of the Green 2000 campaign to change the party constitution. In August, he welcomed the resignation of Principal Speaker Sara Parkin, the leader of Green 2000 proposals. Following this, Baker was elected as Principal Speaker, serving for a year.
Soon after completing his term as Principal Speaker, Baker resigned from the Green Party and joined the Liberal Democrats. He became the editor of Challenge, the journal of the Green Liberal Democrats group. He subsequently devoted his time to campaigning on corporate social responsibility, leading the Business in the Community charity, and subsequently his own Daisywheel Interactive agency, while writing for Ethical Corporation.
- Alex H. Wood, The Times Guide to the House of Commons: April 1992, p.201
- David Kemball-Cook, Chris Mattingly and Mallen Baker, The Green Budget: An Emergency Programme for the UK
- "Mallen Baker: Electoral history and profile", The Guardian
- John Morrisey, "How Green Was My Party?", Synthesis/Regeneration #13
- Nicholas Schoon, "Parkin quits Green Party leadership: Resignation letter condemns 'endless redundant skirmishes' between die-hard faction and reformers", The Independent, 27 August 1992
- Duncan Brack, Why I am a Liberal Democrat, pp.14-16
- "Info", mallenbaker.net
|Principal Speaker of the Green Party of England and Wales