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expert reaction to the annual statistics on the use of animals in scientific procedures in the UK for 2021

The Home Office have published the statistics of scientific procedures on living animals in Great Britain for 2021.


Dr Mark Downs, Chief Executive, Royal Society of Biology (RSB), said:

“The use of animals in research plays an essential role in advancing our knowledge of biology and our understanding of diseases in humans and other animals.

“This role has been exemplified recently in the use of animal models for the development, efficacy and safety testing of vaccines for SARS-CoV-2.

“The UK has been a leader in laboratory animal welfare and culture of care.

“The National Centres for the 3Rs (NC3Rs) has been a fundamental force in driving the development and update of innovative solutions to replace, refine and reduce the use of animals in research and testing.

“The Royal Society of Biology supports the use of animals in research when no alternatives are available, and is committed to promoting openness and transparency in reporting the use of animals for scientific purposes.”


Chris Magee, Head of Policy and Media, Understanding Animal Research (UAR), said:

“There has been a slight increase in the number of experiments this year, but last year’s numbers were only lower due to the Covid lockdowns. It appears that Great Britain is returning to pre-pandemic levels of biomedical research.

“We use a wide range of non-animal tools in the biosciences, including computer models, but animals are still needed to provide the key insights for preventing and treating human and animal suffering.

“Animals provide the critical information for creating most medicines, from Covid vaccines to cancer treatments. However, safety tests are there to prevent greater suffering than would otherwise occur.

“We don’t test cosmetics or cleaning products, and don’t use an animal if there’s an alternative. It is also important that research animals are well-treated, and it is good to note that experiments that cause severe suffering while the animal is still alive remain a small minority.

“The use of animals is not just ethical and necessary, but is of strategic importance to the UK.

“Covid won’t be the last pandemic, and our ability to respond quickly to these threats rests on decades of prior research. The key insights that allowed mRNA Covid vaccines, including those from Moderna and Pfizer, came from experiments using mice, primates and frogs in the late 1990s, whereas the AstraZeneca vaccine used mice, ferrets, primates and pigs.

“It is essential that political parties and governments of all stripes back this work that is so critical to people, animals and the environment.”


Dr Vicky Robinson, Chief Executive, NC3Rs, said:

“The welfare of laboratory animals is understandably one that many people are concerned about. The publication of the annual statistics on the numbers used is often a focal point for debate, but it is important to remember the work that is done all year round to care for the animals and find alternatives to their use. But we need to accelerate these efforts and find more ways to avoid or replace the use of animals.”


Professor Nic Wells, Professor in Translational Medicine, Royal Veterinary College, and Chair of the Animals Sciences Group, Royal Society of Biology, said:

“The increase in the number of animal procedures is not unexpected as the figure was particularly low in 2020 (a drop of 15% on the numbers for 2019), most likely due to the restrictions imposed by the Covid-19 pandemic. There has also been a rise in the number of experimental procedures compared to the number of procedures involving the breeding of genetically altered animals, particularly in the area of applied research, which may reflect a change in research priorities following the Covid pandemic.

“As in previous years, I have provided below a broader narrative and summary of the statistics, looking at the main numbers and the context for some terms.


“Last year, there were 3.06 million scientific procedures involving living animals (this is usually higher than the number of animals used, as under certain conditions an animal may be reused). A procedure is defined as anything that causes pain, suffering, distress or lasting harm equivalent to, or greater than, the insertion of a hypodermic needle in accordance with good veterinary practice (for example a vaccination). This is the threshold.

“The number of procedures was up 6% compared to 2020, which was the lowest number since 2004, most likely reflecting the effects of the Covid-19 pandemic with many institutions delaying or stopping studies using experimental animals in 2020.

“1.73 million (57%) were experimental procedures and 1.33 million (43%) involved the generation or breeding of Genetically Altered (GA) animals. Even if the genetic modification causes no harm (i.e. is below threshold), breeding natural mutants or genetically engineered animals is counted as a procedure. Experimental procedures have increased by 20% and procedures for creation and breeding have decreased by 8% compared to 2020.

“96% of procedures were carried out on mice, fish, birds or rats. Experimental procedures were 54% mice, 15% fish, 11% rats, 13% birds, 5% other species and 1% specially protected species. Procedures for GA animals were 87% mice, 12% fish, 0.7% rats and 0.3% other species. The specially protected species are non-human primates, horses, dogs and cats and applications to work with these species undergo additional scrutiny.

“51% of experimental procedures were for the purpose of basic research, most commonly focusing on the nervous system, the immune system, and cancer. 21% of experimental procedures were for regulatory purposes, a decrease from 33% in 2020. This year there has been a large increase in the proportion of applied research which increased from 10% in 2020 to 27% in 2021.

“The actual severity of experimental procedures on animals were 97% non-recovery (where the animal does not wake up after anaesthesia), sub-threshold, mild or moderate, only 3% were severe.

“The actual severity of procedures for the generation and breeding of GA animals were 98% non-recovery, sub-threshold, mild or moderate, only 2% were severe. 73% of procedures were sub-threshold.

“Mild severity is the equivalent of an injection or having a blood sample taken. Moderate severity is greater than transient pain (for example surgery under anaesthesia followed by painkillers during recovery). Severe suffering is something that we would not wish to endure (for example a heart attack). Animals found dead are commonly classified as severe, as pre-mortality suffering often cannot be assessed. Most severe procedures arise in regulatory testing such as evaluation of toxicity of drugs.”



Statistics of scientific procedures on living animals, Great Britain: 2021’ was published by the Home Office on 30th June 2022.



All our previous output on this subject can be seen at this weblink:



Declared interests

For all experts, no reply to our request for DOIs was received.

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