Blakemore is a patron of Humanists UK (formerly the British Humanist Association) and an Honorary Associate of the Rationalist Association. He is also an Honorary Associate of the National Secular Society. In July 2001 he was one of the signatories to a letter published in The Independent which urged the Government to reconsider its support for the expansion of maintained religious schools, and he was one of the 43 scientists and philosophers who signed and sent a letter to Tony Blair and relevant Government departments, concerning the teaching of Creationism in schools in March 2002. He was also one of the signatories to a letter supporting a holiday on Charles Darwin's birthday, published in The Times on 12 February 2003, and sent to the Prime Minister and the Home Secretary.