A celebrity-backed billboard campaign in London is bringing attention to the realities of factory farming and "humane slaughter" methods used in the UK, particularly CO2 gas chambers for pigs. Project Slingshot, a group of citizens and celebrities, has launched the Ban CO2 Gas Chambers campaign to challenge the meat industry's claim that gassing pigs is humane. Despite pushback, the UK government has confirmed a phase-out plan for CO2 stunning, with evidence suggesting it causes pain and distress to animals before death.

Public figures like Peter Singer, Stella McCartney, and Diane Morgan have supported the campaign, urging the public not to buy into the industry's claims of humane treatment. The billboards aim to raise awareness and prompt action to end the use of CO2 gas chambers in factory farming. With widespread opposition to this method and growing support for animal welfare, efforts like Project Slingshot's are crucial in advocating for more ethical practices in the meat industry.