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Scientists comment on Home Office statistics on scientific procedures on animals.
Chris Magee, Head of Policy and Media, Understanding Animal Research (UAR), said:
“The 2025 statistics once again show the critical role that research animals play across medical, veterinary and environmental research. They also reflect the continued, gradual decline in the use of animals in research as we continue to develop alternatives, a process that has been ongoing since the mid-1970s.
“However, a closer look reveals a dramatic collapse in the number of severe outcomes in regulatory safety tests, from more than 35,000 in 2024 to just 3,500 in 2025, which is a decline of 90% in a single year. These tests are there to make sure that products don’t harm man, animals or the environment and typically require around 300,000 animals, mainly rats and mice, each year. Inevitably, some of these substances will prove not to be as safe as hoped based on earlier non-animal testing, or the test protocol requires the animal is placed at risk, and they are harmed.
“Recently, new ways of safety testing batches of potentially lethal substances have become available, and there was a drop in the number of mice needed for batch potency testing from 52,213 in 2024 to just 412 in 2025 – a decline of 99.2%. Correspondingly, there was a very welcome drop in severe experimental outcomes, in this area of animal use, of 90%.
“UAR has long argued that the key to reducing regulatory animal use is not, as some activists demand, in removing or watering-down safety tests (with all the risks to human, animal and environmental health that that entails), nor in setting arbitrary deadlines for ending animal testing, which have failed everywhere they’ve been tried, but in developing the technology needed to safely make animal tests unnecessary. The latest statistics demonstrate just how effective such an approach can be.”
Dr Doug Brown FRSB, Chief Executive of the Royal Society of Biology, said:
“These annual statistics are an important part of maintaining transparency about how and why animals are used in science.
“They reflect the continued role of animal research across bioscience, from fundamental studies to the development of new medical and veterinary treatments.
“The scientific community remains committed to the principles of the 3Rs – Replacement, Reduction and Refinement, and the Royal Society of Biology fully supports the UK Government’s commitment and investment to accelerate the development and uptake of alternative approaches to animal use, wherever possible.
“Promising advances in non-animal methods and technologies are creating new opportunities to complement, and in some areas replace, the use of animals in research.
“At the same time, animal research remains necessary in areas where complex biological systems cannot yet be replicated by other methods. Animal studies are increasingly used alongside a range of other approaches, and continued progress in bioscience will depend on maintaining a balanced, science-led approach that supports innovation in alternatives alongside the responsible use of animals where needed.
“The Royal Society of Biology supports the use of animals in research when no valid alternatives are available, and remains committed to promoting openness and transparency in reporting the use of animals for scientific purposes.”
Professor Sarah Bailey, University of Bath and Academic Co-Chair of the UK Bioscience Sector Coalition (UKBSC), convened by RSB, said:
“The publication of the 2025 animal research statistics provides a meaningful baseline against which the Government’s “Replacing animals in science strategy” can be measured. As implementation of the strategy progresses, these data will be essential for tracking where change is being achieved and where animal research remains scientifically necessary.
“The statistics reinforce an important reality: despite continued advances in non-animal methods, there are still areas of biomedical research such as development, ageing, the brain, the immune system, where whole-animal models remain essential to understanding complex biological processes. The figures show that the majority of animal procedures continue to support this type of basic research (54%).
“A further 26% of procedures are in applied research to develop new approaches for preventing and treating disease. Most studies are investigating animal diseases and disorders.
“Regulatory testing accounts for 19% of procedures, but this category has fallen by around 20% compared with 2024, reflecting progress in reducing animal use where scientifically validated alternatives are available.
“Importantly, several regulatory tests identified in the Government’s strategy were already not being used during 2025. Combined with planned improvements to Home Office data collection and reporting, future statistics should provide a clearer picture of how the strategy is accelerating the replacement of animal use, particularly in regulatory testing.”
Hannah Hobson, Head of Communications and Engagement at Understanding Animal Research, said:
“Animal research remains a small but vital part of the quest for new medicines, vaccines and treatments for humans and animals. Alternative methods are increasingly being phased in but, until we have sufficient reliable alternatives available, it is important that organisations that use animals in research maintain the public’s trust in them. By providing this level of information about the numbers of animals used, and the experience of those animals, as well as details of the medical breakthroughs that derive from this research, these Concordat on Openness signatories are helping the public to make up their own minds about how they feel about the use of animals in scientific research in Great Britain.”
Sarah Hart-Johnson, Director of the Crick’s Biological Research Facility, said:
“These statistics reflect both the scale and complexity of the science taking place across the institute and the important work we support through collaborations with university partners. As a national biomedical research institute, our facilities and expertise enable research that extends far beyond our own laboratories.
In areas where whole biological systems need to be understood or complex diseases modelled, animals remain an essential part of research. Their use is closely integrated with complementary non-animal methods and follows rigorous scientific and ethical review.
Reducing reliance on animals is fundamental in the way we conduct research, ensuring our science remains robust and impactful. Our scientists are leaders in developing and sharing new approaches, including organoids, organs-on-chips, stem cell-based models and computational methods.”
Professor Jon Simons, Head of the School of Biological Sciences at the University of Cambridge, said:
“While animal use in research remains an important part of advancing scientific discovery and improving our understanding of complex diseases, it is equally important to recognise the need for continued progress in identifying alternative research models. We are committed to advancing new approaches and putting them into practice to complement or replace animal studies with robust and evidence-based alternatives.”
James Bussell, Director of Biomedical Services at the University of Oxford, said:
“Across the University of Oxford, researchers are investing in and developing innovative approaches that can replace or reduce the use of animals in research wherever scientifically possible. However, for some areas of biomedical research, carefully regulated animal studies remain an essential part of advancing our understanding of disease and developing new treatments. We are committed to ensuring that any such work is undertaken only where necessary and under rigorous oversight.
The welfare of the animals in our care is of paramount importance. We work continuously to improve standards of care and husbandry, while ensuring that every project involving animals meets strict legal, ethical and regulatory requirements.”
Professor Geraint Rees, UCL Vice-Provost (Research, Innovation & Global Engagement), said:
“Biomedical scientists at UCL use every tool at their disposal to develop life-saving treatments and improve human health. Animals are used in research only when necessary, as our scientists continually develop new ways to replace animals in research, reduce their usage, or refine their methods to mitigate harm, while maintaining the highest standards of high-impact, innovative science.”
Dr Ivan Pavlov, Head of Preclinical Good Research Practice Policy at the Medical Research Council, said:
“Research involving animals continues to underpin many of the advances that improve lives. While alternatives are increasingly available, some questions about how complex systems, such as the brain, function can currently only be addressed using living tissues.
For example, at the MRC Laboratory of Molecular Biology, research involving mice helped uncover new complexity in how key proteins interact to regulate daily rhythms within a functioning neural circuit, challenging the long-held model of how the body’s internal clock keeps time.
These findings provide important new insights into how the body’s internal clock operates and could support the future development of improved treatments for conditions such as sleep disorders and depression.
We remain committed to supporting the highest standards of animal welfare and to being open about the role that animals continue to play in medical research.”
Dr Catherine Martin, Vice-Principal Corporate Services, University of Edinburgh, said:
“Studies involving animals enable researchers at the University of Edinburgh to advance understanding of conditions such as Alzheimer’s, heart disease and many forms of cancer, and to help improve animal health.
We strive to develop approaches to reduce, refine and replace animal models, and only use animals in research when no suitable alternatives exist. Demonstrating our commitment to the 3Rs, fewer animal procedures were carried out at the University in 2025 than in previous years.
The University is committed to being open about its use of animals in research and we have been recognised by Understanding Animal Research as a Leader in Openness since 2020. We continue to take steps to further our transparency, including recently developing a virtual tour of our animal facilities to help demonstrate how we uphold the highest standards of animal welfare.”
Julie Keeble, Director of Biological Services and Co-Chair of the Centre for 3Rs & Translational Innovation at King’s College London, said:
“The responsible use of animals in research remains essential to advancing world class research, and through initiatives such as the Centre for the 3Rs in Translational Innovation at King’s, we are committed to ensuring this work is carried out to the highest standards of care, welfare and scientific rigour. At the same time, we are actively supporting the development and adoption of alternative methods, while recognising that animal models continue to play a vital role where no viable alternatives yet exist.”
David Duncan, University of Glasgow Secretary and Deputy Vice Chancellor, said:
“Research using animals makes an important contribution to the treatment and cure of major human diseases and viruses, including cancers, Alzheimer’s disease, flu and arthritis. At the University of Glasgow animals are used in research only where it is essential, and we remain dedicated to the principles of reduction, refinement, and replacement.
The University is committed to the development of alternative methods – such as computer modelling, tissue culture, cell and molecular biology, and research with human material – but some work involving animals must continue for further advances in medical sciences to be made. All research undertaken on animals is conducted under strict ethical and welfare guidelines, under licence by the Home Office.”
Dr Maria Kamper, Strategic Director of the Biological Services Facility at The University of Manchester, said:
“Scientific research involving animals remains a cornerstone of our ability to understand complex diseases and develop life-saving medical breakthroughs. At The University of Manchester, we recognize that the privilege of conducting this research carries a profound responsibility – not only to the animals in our care but to the public we serve. Our commitment to the Concordat on Openness is reflected in our award-winning digital platforms, where we share the reality of our work through virtual tours, detailed case studies, and transparent data. However, transparency is only possible because of our foundational ‘culture of care’. By prioritizing exceptional animal husbandry, staff wellbeing, and ethical accountability, we ensure that our scientific excellence is always matched by our integrity. As we share our latest statistics, we remain dedicated to a sustainable research environment where open communication and world-class welfare standards go hand-in-hand to benefit society as a whole.”
Professor Marina Botto, Director of Bioservices at Imperial College London, said:
“At Imperial, our researchers are committed to replace animal use where possible, reduce the number of animals needed, and refine procedures to enhance welfare. Yet, animal models remain a vital part of our biomedical research, helping researchers to uncover groundbreaking insights into important health issues like dementia, aging, gut health, cancer, lung and kidney diseases. Our drive towards both transparency and continuous improvement in animal research are highlighted by the high standard of our Facilities and the commitment of our 3RsHub.”
https://www.gov.uk/government/statistics/scientific-procedures-on-living-animals-great-britain-2025
Declared interests
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