The CEE Bill was developed by scientists, academics and lawyers, along with members of the Big Ask campaign, which led to the Climate Change Act back in 2008. The campaign for the CEE Bill was launched in August 2020 and the CEE Bill introduced in Parliament the following month as a Private Members’ Bill. With the new Parliament in 2021, the CEE Bill was reintroduced in June, again as a Private Members' Bill.


The Bill was first introduced in September 2020 and gained the maximum support of cosponsors with 12 members of parliament (MPs) from seven different parties. Cosponsors are MPs who put their name to a Bill in order to present it in Parliament.

The Bill (like nearly all Private Member's Bills) fell in the last Parliament. A new Parliament began in May 2021, and the CEE Bill was updated, strengthened and reintroduced in Parliament again as a Private Members' Bill on 21st June. Caroline Lucas (Green) was the primary sponsor of the Bill again, alongside the following co-sponsors; Barry Gardiner (Labour), Clive Lewis (Labour), Alex Sobel (Labour), Ed Davey (Lib Dem), Sarah Olney (Lib Dem), Alan Brown (SNP), Brendan O'Hara (SNP), Ben Lake (Plaid Cymru), Liz Saville-Roberts (Plaid Cymru), Stephen Farry (Alliance) and Claire Hanna (Social Democrat and Labour Party).