New Home Office statistics covering scientific procedures on living animals in 2025 have revealed a significant reduction in severe outcomes for animals, particularly within regulatory safety testing. The data indicates a 90% decline in the number of severe outcomes in these tests, falling from over 35,000 in 2024 to just 3,500 in 2025. This substantial drop is largely attributed to the introduction of new methods for safety testing, according to experts.
Chris Magee, Head of Policy and Media at Understanding Animal Research (UAR), highlighted the dramatic shift, noting that these regulatory tests typically involve around 300,000 animals, predominantly rats and mice, each year. He also pointed to a remarkable 99.2% decrease in the number of mice required for batch potency testing, dropping from 52,213 in 2024 to just 412 in 2025. This area also saw a welcome 90% reduction in severe experimental outcomes.
The scientific community views these statistics as a testament to the effectiveness of developing advanced technologies to make animal tests unnecessary, rather than imposing arbitrary bans or weakening safety regulations. Dr Doug Brown FRSB, Chief Executive of the Royal Society of Biology, underscored the importance of these annual statistics for maintaining transparency regarding animal use in science. He affirmed the scientific community's commitment to the '3Rs' principles: Replacement, Reduction, and Refinement, and praised the UK Government's investment in accelerating the development of alternative approaches.
While acknowledging promising advancements in non-animal methods, Dr Brown also stressed that animal research remains essential for areas where complex biological systems cannot yet be replicated by other means. He advocated for a balanced, science-led approach that supports innovation in alternatives while responsibly utilising animals where necessary. Professor Sarah Bailey, from the University of Bath and Academic Co-Chair of the UK Bioscience Sector Coalition, added that the 2025 statistics will serve as a crucial baseline for measuring the progress of the Government’s “Replacing animals in science strategy.”
The data provides key insights into where changes are being achieved and where animal research continues to be scientifically indispensable. The figures reflect a long-term, gradual decline in the overall use of animals in research, a trend that has been observed since the mid-1970s as alternatives continue to be developed.