Mayo rose to prominence as director of the New Economics Foundation (NEF) from 1992 to 2003. He led NEF from two to fifty staff, creating the leading 'think-and-do tank', looking at ethical market activity, local economies and public service reform. NHS Foundation Trusts were an idea partly inspired by NEF and Mayo, particularly his October 2001 pamphlet, "The Mutual State", published with Mutuo, a think tank set up by the Co-operative Party. NEF also co-ordinated the Jubilee 2000 campaign during this time, for which Mayo was the strategist. It gained 24 million signatures for the worldwide petition on development and poverty.