2,537,507
Procedures were carried out using animals in British laboratories in 2025
1,219,976
Procedures were carried out for the creation and breeding of genetically altered animals
17,593
Experiments were assessed as 'severe'
17,317
Experiments were carried out on specially protected species (cats, dogs, horses and monkeys)
The 2025 annual statistics of scientific procedures using living animals in Great Britain were released by the Home Office in July 2026.
The report sets out how many animals of each species were used in scientific procedures (experiments) in Great Britain during 2025. It also includes the number of animals involved in the creation and breeding of genetically altered animals that were not themselves used in experiments. In addition, the report provides information on the severity of the procedures, their purpose, the disease areas being studied, and where the animals were born.
A note on terminology
The Home Office describes every instance of animal use as a ‘regulated procedure‘, which is defined under the Animal (Scientific Procedures) Act 1986 (ASPA) as ‘any procedure applied to a protected animal for a qualifying purpose which may have the effect of causing the animal a level of pain, suffering, distress or lasting harm equivalent to, or higher than, that caused by the introduction of a needle in accordance with good veterinary practice.’
This umbrella definition covers a wide range of circumstances, and could include tests, experiments or other methods to use animals for scientific, regulatory or educational purposes. The term also covers the the genetic modification of animals, including the breeding and creation of genetically altered animals which are not later used in experiments.
The annual statistics report on both the procedures carried out using animals directly for experimental purposes, and those to create and breed genetically altered animals. To make this article easier to read, we use the term ‘procedures’ when referring to the overall Home Office statistics that include the creation of genetically altered animals, and ‘experiments’ when referring specifically to experimental research using animals.
Read more details about the report below and find out what you can do to help animals in laboratories.
Key findings from the 2025 statistics:
While the 2025 statistics show a small decrease compared to the previous year, a staggering 2,537,507 procedures using animals were still carried out in British laboratories: a disappointing 3.8% decrease compared to 2024.
In total, 2,457,619 animals were used in 2025, including mice, rats, fish, rabbits, dogs, cats, monkeys and horses.
The annual statistics include both the number of experiments directly using animals (1,317,531), and the number of procedures carried out for the creation and breeding of genetically altered animals, where the animals were not used in experiments (1,219,976, around 48% of total procedures – a 1% increased compared to 2024).
Of the total experiments carried out in 2025, 734,967 used mice (56%), 215,789 used fish (16%), 120,458 used rats (9%) and 129,947 used birds (10%).
Of these:
- Just 19% (246,270) were carried out for regulatory purposes (such as testing new drugs or safety testing of chemicals), challenging the assumption that most animal experiments are required by regulations.
- 17,593 were classified as ‘severe’ (1.3%) and 380,935 were classed as ‘moderate’ (28%) – each causing considerable pain, discomfort and distress to the animals involved.
- Around half (54%) of all experiments were carried out for basic research (“curiosity-driven” research to gain knowledge and understanding of a disease), while around a quarter (26%) were for applied research (study of human diseases and the development of treatments). Neither of these types of research are required to use animals to fulfill regulatory or law requirements.
- 1,093,576 experiments were carried out in England (83%), 213,940 in Scotland (16%), and 10,015 in Wales (0.8%).
1,706
dogs were used
in experiments.
1,775,356
mice were used
in experiments.
1,845
monkeys were used
in experiments.
Experiments using specially protected species
The number of experiments using specially protected species (dogs, cats, horses and monkeys) increased by 7% from 16,147 in 2024 to 17,317 in 2025.
- 2,889 experiments used 1,706 beagles or other dogs (a 3% increase in the number of animals used, and a 9% increase in the number of experiments compared to 2024). 2,101 experiments were for regulatory purposes – 1,428 of which were for repeated dose toxicity testing, with 31% lasting for longer than 90 days.
- 12,101 experiments used 100 horses, (a 67% increase in the number of animals used, and a 5% increase in the number of experiments compared to 2024) with the majority used in the routine production of blood based products.
- 1,856 monkeys were used in 2,236 experiments (a 25% increase in the number of animals used, and a 15% increase in the number of experiments compared to 2024), with 78% used for repeat dose toxicity testing, and 22% for up to 90 days.
- 19 cats were used in 91 experiments (a 46% decrease in the number of animals used, but an 11% increase in the number of experiments compared to 2024, a worrying increase meaning that at least some cats were used in experiments multiple times).
There was a 40% increase in the number of horses used in 2025 compared to the previous year
A further key issue is the additional stress experienced by animals who were born abroad and transported to be used in British labs. 95% of the cynomolgus monkeys used in 2025 were imported from Africa or Asia, who alongside being destined for use in experiments, would also have had to endure significant stress caused by transportation.
These statistics provide an incomplete picture of the true number of animals used in British labs each year, as some animals fall outside of the protection of the law, and so are not counted in the statistics – such as those in their embryonic form. In addition, as every country collects and shares animal use statistics in different ways, it is impossible to know the true number of animals used globally in research each year, but estimates range from 100-150 million animals.
An important point
The annual statistics publication only includes experiments performed using living animals that are protected under the Animals (Scientific Procedures) Act 1986 (ASPA).
Animals that fall outside of ASPA are not counted in the annual statistics.
In addition, individual animals can be used more than once in different experiments, but the statistics only capture the first time an animal is used in an experiment. Therefore the figures do not fully reflect the true number of experiments carried out using animals each year, which is likely to be significantly higher.
Which animals does ASPA cover?
ASPA only covers protected animals, which according to the Home Office are defined as: “Any living vertebrate, other than man, and any living cephalopod. The Animals (Scientific Procedures) Act 1986 also counts embryos after two-thirds of gestation, and fish and amphibian larvae after they become capable of free feeding as protected animals.”
The use of protected animals is regulated by the Home Office under ASPA, but they can still be used in research.
Some animals have additional protections to minimise their use. These specially protected animals are dogs, cats, horses and non-human primates. These animals are still used in research, but the law states they can only be used when other species are unsuitable or unavailable.
How you can help
Whilst 2025’s figures are the lowest since 2001, change in this area is still too slow and we won’t rest until this number reaches zero.
This is why we are calling on the UK government to implement Herbie’s Law: new legislation to support scientists to move away from animal-based experiments and instead focus on human-specific technologies. We want the UK to become a research superpower, leading the way towards an animal-free future for science.
