In 2013, nine of the UK's leading animal welfare groups formed a collaboration called the Cat Population Control Group (CPCG) with the aim of maximising the effectiveness of cat neutering efforts in the UK. Despite the best efforts of the UK's rescue organisations in providing subsidised neutering schemes - amounting to in excess of £9 million per annum - the cat population had spiralled out of control. Informed by behavioural insights, the CPCG revised its public communications about cat neutering and has developed a number of work programmes with the aim of making neutering services accessible to all cat owners. Since its inception, the CPCG has seen a year-on-year increase in the neutering rate of the UK's owned cats - from 86% in 2012 to 92% in 2015 and a notable shift in public attitudes about cat neutering. In a short space of time, the CPCG has made some significant improvements for cat welfare - and has developed the first effective model of charity collaboration focused on tackling the root cause of a specific animal welfare issue.