Zero Hour (formerly the CEE Bill Alliance) is a UK-based environmental campaign organisation founded in August 2020 that primarily advocates for the Climate and Nature Bill, a private member's bill in the UK Parliament.
Since October 2025, the organisation has served as secretariat for the Climate and Nature Crisis Caucus, a cross-party parliamentary group.
Zero Hour was founded in August 2020 as the CEE Bill Alliance to campaign for urgent, science-led and joined-up climate and nature legislation for the UK. Supporters of the campaign drafted the 'Climate and Ecological Emergency Bill' (also known as the 'Three Demands Bill'), which was promoted ahead of the 2019 general election. The bill sought to establish legally-binding climate and nature objectives for the UK and proposed creating a citizens' assembly to help develop an integrated government strategy.
On 2 September 2020, the Climate and Ecology Bill was presented in the House of Commons by Caroline Lucas, then Green Party MP. Lucas represented the bill in the Commons on 21 June 2021. Lord Redesdale introduced the bill in the House of Lords on 25 May 2022 via the ballot procedure, where it completed all Lords stages, but did not advance through the Commons before the session ended.
Olivia Blake (Labour) introduced the bill via the ten minute rule procedure on 10 May 2023, and Alex Sobel (Labour Co-operative) presented it on 21 March 2024, when its short title was revised to the Climate and Nature Bill. Roz Savage (Lib Dem) advanced the bill to a second reading for the first time on 24 January 2025 via the ballot procedure. The Labour Government did not support the progression of Savage's bill, but did commit to alternative measures.
Zero Hour primarily campaigns for the adoption and implementation of the Climate and Nature Bill. The organisation has also critiqued government legislation on climate and environmental policy.
As of February 2026, Zero Hour reports that 386 local councils have passed motions supporting the bill, and 192 MPs have pledged support. It promotes public support for the bill through petition campaigns, letter-writing initiatives, public events, and motions passed by local authorities.
For example, in 2024, Zero Hour campaigners contacted candidates and then MPs ahead of the private members' bill ballot on 5 September 2024. Savage was successful in the ballot and selected the Climate and Nature Bill.
The organisation also provides information on climate and environmental legislation and parliamentary processes, creates digital lobbying tools and videos, and organises events, webinars, public forums, and parliamentary lobby days.
While the bill has not yet passed into law, Zero Hour states that it has retained cross-party parliamentary support for its efforts, and claims that its advocacy contributed to the Labour Government commitments announced in July 2025, including an annual climate and nature statement to Parliament (first made by Ed Miliband on 14 July 2025), stronger collaboration between climate and nature committees and ministries, better accounting of overseas emissions, public engagement strategies, and a revised statutory plan for nature protection.
Zero Hour states that it monitors parliamentary developments and provides analysis to parliamentarians and supporters through the Climate and Nature Crisis Caucus, which it serves as secretariat, and has worked with parliamentarians to seek to Government bills (such as the Environment Act 2021). The organisation has also organised UK-wide political declarations and published reports, including Net Zero: The Ambition Gap and Creating a Nature-Rich UK.
The BBC and The Guardian reported extensively on the bill's second reading in January 2025, when Labour MPs were directed to oppose its progression. Forbes and The BMJ have also covered Zero Hour's work, alongside The Ecologist, Byline Times, Business Green, The Tablet and Edie.
The campaign's activities have received endorsements from public figures including wildlife presenter Chris Packham and economist Partha Dasgupta, who was one of over 1,100 scientists and health professionals who signed an open letter calling on MPs to support the bill.
Zero Hour has received recognition for its work, including a bronze Charity Film Award from the Smiley Movement in February 2025 for its short film, What Has Nature Ever Done For Us?.
Zero Hour has campaigned for the Climate and Nature Bill since 2020, coordinating with MPs and Peers who have presented and co-sponsored it in the UK Parliament.
According to the organisation, approximately 2,800 organisations, politicians and scientists, and 75,300 members of the public, support the bill. Supporters include major conservation charities such as the National Trust and Friends of the Earth, alongside academics, religious leaders, trade unions, businesses, and local government bodies.
The bill has faced opposition from Labour ministers, who sought removal of clauses requiring UK compliance with international climate targets, and from many Conservative MPs, who criticised the proposed citizens' assembly as "undemocratic". The National Federation of Builders opposed the bill as "well-intentioned", but likely to lead to "unintended consequences that may cause more harm than they solve". In addition, right-wing commentators raised economic concerns online, although the Countryside Alliance (which does not support the bill) characterised some of these criticisms as "ill-founded". A similar legislative proposal, the 'Living Planet Bill', has been proposed but not published by WWF-UK.
According to its financial statement for the year 2024-25, Zero Hour Limited held total assets of ã112,503 and employed nine members of staff. Its funding is received through donations and grants from charitable trusts, including Polden-Puckham Charitable Foundation, Joseph Rowntree Charitable Trust, Esmée Fairbairn Foundation and Andrew Wainwright Reform Trust.