Between 1983 and 1995, Howitt served as a councillor on Harlow District Council. This included three years as Leader of the council between 1991-1994. During this period he led ground-breaking work related to the assessment of local government’s environmental impact.
In the 1987 UK general election, Howitt was the Labour Party candidate in Billericay, but with only 19.4 percent of the vote, he came third behind the Conservative Teresa Gorman and Social Democrat Michael Birch. Billericay is staunchly conservative, with the party holding the seat since 1966.
Howitt was a member of the Labour Party's National Policy Forum between 1994 and 2016 and a member of Labour Party Britain in the World Policy Commission since 1997.
From 1994 Howitt has also been Honorary Vice-President of the UK Local Government Association and Chair of the South and East Economic Development Strategy Association.