The Government is committed to ensuring that non-human primates used in scientific procedures are sourced responsibly and used only where no suitable alternative is available. In 2025, 1,845 non-human primates were used for the first time in scientific procedures in Great Britain. All marmosets, tamarins and rhesus monkeys were born at licensed establishments in the UK, while the majority of cynomolgus monkeys were born overseas, but were not sourced from the wild.

Following advice from the Animals in Science Committee, the Home Office strengthened its sourcing requirements from 1 August 2025 so that non-human primates should come from established captive-breeding populations rather than being sourced from the wild. These requirements are supported by a time-limited transitional arrangement and a commitment to review their operation.

The Government supports the use of UK-bred non-human primates where suitable animals are available. However, sourcing decisions must take account of scientific requirements, animal welfare, biosecurity and the availability of appropriate breeding populations. The Home Office will continue to monitor sourcing data and the effect of the strengthened requirements.

The Government is also investing £75 million through its strategy to support the development, validation and uptake of alternatives to animal use.

The Government is committed to ensuring that non-human primates used in scientific procedures are sourced responsibly and used only where no suitable alternative is available. In 2025, 1,845 non-human primates were used for the first time in scientific procedures in Great Britain. All marmosets, tamarins and rhesus monkeys were born at licensed establishments in the UK, while the majority of cynomolgus monkeys were born overseas, but were not sourced from the wild.

Following advice from the Animals in Science Committee, the Home Office strengthened its sourcing requirements from 1 August 2025 so that non-human primates should come from established captive-breeding populations rather than being sourced from the wild. These requirements are supported by a time-limited transitional arrangement and a commitment to review their operation.

The Government supports the use of UK-bred non-human primates where suitable animals are available. However, sourcing decisions must take account of scientific requirements, animal welfare, biosecurity and the availability of appropriate breeding populations. The Home Office will continue to monitor sourcing data and the effect of the strengthened requirements.

The Government is also investing £75 million through its strategy to support the development, validation and uptake of alternatives to animal use.

The Government is committed to ensuring that non-human primates used in scientific procedures are sourced responsibly and used only where no suitable alternative is available. In 2025, 1,845 non-human primates were used for the first time in scientific procedures in Great Britain. All marmosets, tamarins and rhesus monkeys were born at licensed establishments in the UK, while the majority of cynomolgus monkeys were born overseas, but were not sourced from the wild.

Following advice from the Animals in Science Committee, the Home Office strengthened its sourcing requirements from 1 August 2025 so that non-human primates should come from established captive-breeding populations rather than being sourced from the wild. These requirements are supported by a time-limited transitional arrangement and a commitment to review their operation.

The Government supports the use of UK-bred non-human primates where suitable animals are available. However, sourcing decisions must take account of scientific requirements, animal welfare, biosecurity and the availability of appropriate breeding populations. The Home Office will continue to monitor sourcing data and the effect of the strengthened requirements.

The Government is also investing £75 million through its strategy to support the development, validation and uptake of alternatives to animal use.

Under the Animals (Scientific Procedures) Act 1986, severity assessments measure harms to an animal during a regulated procedure and reflect the highest severity experienced during that procedure, including any cumulative procedural effects. Harms arising from non-procedural events, such as transport and housing, are therefore not within the scope of the severity assessment framework. These matters are instead addressed through separate welfare, transport, licensing and care requirements.

The minimum separation ages for non-human primates were not reassessed as part of the 2026 Code update. The Code clarified and consolidated the legal minimum standards in force since 2017; it did not change them. Licensed establishments must meet those standards and should also consider current evidence-based advice and leading practice.

The number and type of regulated procedures carried out can vary from year to year, reflecting factors such as scientific and public health priorities, scientific innovation, research funding, regulatory requirements, and the availability of suitable non-animal alternatives.

The Government’s Replacing Animals in Science strategy, backed by £75 million in funding, sets out measures to accelerate the development, validation and uptake of non-animal methods, including through increased research investment and the establishment of a UK Centre for the Validation of Alternative Methods.

The number and type of regulated procedures carried out can vary from year to year, reflecting factors such as scientific and public health priorities, scientific innovation, research funding, regulatory requirements, and the availability of suitable non-animal alternatives.

The requirements for regulatory testing are set by the relevant product regulators, including the Medicines and Healthcare products Regulatory Agency for medicines and the Health and Safety Executive for chemicals.

The Government’s Replacing Animals in Science strategy, backed by £75 million in funding, sets out measures to accelerate the development, validation and uptake of non-animal methods.

The annual statistics do not separately identify dedicated pharmacokinetic studies or dedicated cardiovascular safety studies. Pharmacokinetic procedures are reported within the wider “kinetics” category, which also includes toxicokinetic and residue depletion studies. It is therefore not possible to provide the requested figures from the published statistics.

The Government’s strategy, Replacing animals in science, sets targets to use validated alternative methods to reduce the use of dogs and non-human primates in dedicated pharmacokinetic studies for human medicines by at least 35% by 2030, and in dedicated cardiovascular safety studies by at least 50% by 2030.

The Government’s strategy sets out measures to accelerate the development, validation and adoption of alternative methods, increased research investment, the establishment of a UK Centre for the Validation of Alternative Methods, greater collaboration between regulators, researchers and industry, and work to support regulatory acceptance. It highlights technologies including artificial intelligence, organoids and three-dimensional cell systems as offering opportunities to reduce reliance on animals. Under the Animals (Scientific Procedures) Act 1986, animals may be used only where no scientifically satisfactory non-animal method is available.

The Government has considered the implications of the Animals in Science Committee’s advice, including the findings on page 14 of its October 2024 report on non-human primates used in service licences. The Minister for the Home Office (Lord Hanson of Flint) has formally responded to the Committee, and that response is available at:

https://www.gov.uk/government/publications/non-human-primates-used-in-service-licences-response-from-lord-hanson.

This project, among other research, sits within the Government’s broader strategy to support research that advances the understanding of major public health challenges. The expected scientific benefits of this work include improving understanding of how brain cells, together with brain chemicals, support key mental processes including learning, memory, planning and decision-making. In the longer term, this evidence base is expected to aid the development of therapies for neurological and neuropsychiatric conditions, such as depression, addiction and dementia.

All project licence applications under the Animals (Scientific Procedures) Act 1986 (ASPA) are assessed by medically or veterinary qualified inspectors within the Animals in Science Regulation Unit (ASRU). Under ASPA, no project can be granted without a harm-benefit analysis, where an ASRU inspector makes a rigorous assessment of the scientific rationale for the programme of work, and must assess that the harms of the proposed project are justified by the likely benefits. Inspectors assess the appropriateness of the scientific methods being proposed for achieving the stated benefits and must be confident that these benefits are likely to be realised. The project must also demonstrate full application of the legal requirements of replacement, reduction and refinement (the 3Rs). This means that animal use cannot be approved if a practicable nonanimal alternative method exists, the number of any animals used must be minimised, and the most refined methods must be used for animal testing to minimise harms.

This project, among other research, sits within the Government’s broader strategy to support research that advances the understanding of major public health challenges. The expected scientific benefits of this work include improving understanding of how brain cells, together with brain chemicals, support key mental processes including learning, memory, planning and decision-making. In the longer term, this evidence base is expected to aid the development of therapies for neurological and neuropsychiatric conditions, such as depression, addiction and dementia.

All project licence applications under the Animals (Scientific Procedures) Act 1986 (ASPA) are assessed by medically or veterinary qualified inspectors within the Animals in Science Regulation Unit (ASRU). Under ASPA, no project can be granted without a harm-benefit analysis, where an ASRU inspector makes a rigorous assessment of the scientific rationale for the programme of work, and must assess that the harms of the proposed project are justified by the likely benefits. Inspectors assess the appropriateness of the scientific methods being proposed for achieving the stated benefits and must be confident that these benefits are likely to be realised.

The project must also demonstrate full application of the legal requirements of replacement, reduction and refinement (the 3Rs). This means that animal use cannot be approved if a practicable nonanimal alternative method exists, the number of any animals used must be minimised, and the most refined methods must be used for animal testing to minimise harms.

This project, among other research, sits within the Government’s broader strategy to support research that advances the understanding of major public health challenges. The expected scientific benefits of this work include improving understanding of how brain cells, together with brain chemicals, support key mental processes including learning, memory, planning and decision-making. In the longer term, this evidence base is expected to aid the development of therapies for neurological and neuropsychiatric conditions, such as depression, addiction and dementia.

All project licence applications under the Animals (Scientific Procedures) Act 1986 (ASPA) are assessed by medically or veterinary qualified inspectors within the Animals in Science Regulation Unit (ASRU). Under ASPA, no project can be granted without a harm-benefit analysis, where an ASRU inspector makes a rigorous assessment of the scientific rationale for the programme of work, and must assess that the harms of the proposed project are justified by the likely benefits. Inspectors assess the appropriateness of the scientific methods being proposed for achieving the stated benefits and must be confident that these benefits are likely to be realised.

The project must also demonstrate full application of the legal requirements of replacement, reduction and refinement (the 3Rs). This means that animal use cannot be approved if a practicable nonanimal alternative method exists, the number of any animals used must be minimised, and the most refined methods must be used for animal testing to minimise harms.

The Government is committed to reducing the use of animals in science, including non‑human primates, through the Replacing Animals in Science strategy, which supports the development, validation and uptake of alternative methods. The use of non‑human primates is already subject to stringent controls and is permitted only where no validated alternatives exist and where justified by the potential benefits. The strategy includes targeted ambitions to reduce reliance on specific animal models as validated approaches are developed. The Government will report on progress through the strategy’s delivery update and associated performance framework, to be published later in 2026.

An approach to measure progress in reaching the target to reduce such use by at least 35% by 2030 is being developed with DSIT colleagues and will be included in a strategy delivery update published later in 2026.

The Home Office does not presently aggregate data on the number of dogs and non-human primates used specifically in dedicated pharmacokinetic studies for human medicines conducted under the Animals (Scientific Procedures) Act 1986. Information on estimated numbers of animals to be used over the lifetime of the licence relevant to such studies may be held within individual project licence records for regulatory purposes.

The Home Office does not publish a separate aggregated category for the number of dogs and non-human primates used specifically in dedicated pharmacokinetic studies for human medicines for publication purposes conducted under the Animals (Scientific Procedures) Act 1986. While information relevant to such studies may be held within individual project licence records for regulatory purposes, there is no distinct reporting category for them in the published in the annual statistics.

The target to reduce the use of dogs and non-human primates in dedicated pharmacokinetic studies for human medicines by at least 35% by 2030 forms part of the Government broader programme Replacing animals in science: A strategy to support the development, validation and uptake of alternative methods. This number was agreed following discussions between regulators, research funders and officials on what was considered to be challenging while also likely being scientifically achievable.

The Government welcomes the advice provided by the Animals in Science Committee (ASC) on non-human primates used in service licences and is carefully considering its recommendations to inform policy and regulatory practice.

The Government will publish its response by the end of June 2026.

The Home Office does not hold centrally collated figures on expected number of procedures to be carried out under service project licences involving dogs or non-human primates in each of the last five years.

Project licences authorise programmes of work according to the scientific need set out in the application, rather than against a single centrally recorded expected procedures total. Information on the expected number and types of animals to be used is set out in published non-technical summaries for each of the licensed programmes of work – published at: https://www.gov.uk/government/collections/non-technical-summaries-of-projects-granted-under-aspa.

The numbers of service project licences are based on information provided during the application process, with figures drawn from the Home Office’s Animals in Science Regulation Unit (ASRU) e‑licensing system. The total number of service project licences granted in each of the last five years are as follows:

2022 – 21 service licenses
2023 – 27 service licenses
2024 – 18 service licenses
2025 – 25 service licenses
2026 – 7 service licenses (to date)

The number of service project licences involving dogs in each of the last five years are as follows:

2022 – 3 service licenses
2023 – 3 service licenses
2024 – 3 service licenses
2025 – 7 service licenses
2026 - 0 service licences (to date)

The number of service project licences involving non-human primates in each of the last five years are as follows:

2022 – 1 service license
2023 – 2 service licenses
2024 – 0 service license
2025 – 3 service licenses
2026 – 0 service licenses (to date)

All project licence applications, including service licences which use specially protected species such as dogs and non-human primates, are subject to a rigorous harm-benefit analysis (HBA), required under the Animals (Scientific Procedures) Act 1986 (ASPA). The HBA ensures that a project is only granted where a Home Office Inspector is satisfied that the likely harms to animals, including pain, suffering, distress and any lasting harm, are justified by the expected benefits for humans, animals or the environment.

Under ASPA, projects proposing the use of specially protected species may only be authorised where no animal of lower sentience can be used to achieve the scientific objectives. In all cases, the principles of replacement, reduction and refinement (the 3Rs) must be fully applied. This means that animal use is permitted only where no validated alternative exists, the minimum number of animals is used, and the most refined methods are used to minimise harm.

The Home Office publishes annual statistics of scientific procedures on living animals in Great Britain, which break down procedures by species, type of procedure, and actual severity experienced by animals. They are available at: https://www.gov.uk/government/collections/statistics-of-scientific-procedures-on-living-animals. Information on the severity of procedures involving NHPs and dogs is set out in Table 3.1, with severity categorised under ASPA as non-recovery, mild, moderate or severe.

Additionally, the Home Office expects to respond to recommendations from the Animals in Science Committee on the use of NHPs in service licences, which is aimed at further strengthening protections for NHPs used in science for service licences.

There is no impact from the number of experiments on (a) beagles (b) non-human primates and (c) rabbits on progress towards the Government’s alternatives strategy. This is because licences for the use of animals in scientific procedures may only be granted only where there is robust scientific justification, no validated nonanimal alternative exists, and use is fully compliant with the requirements of the Animals (Scientific Procedures) Act 1986.

This Government remains firmly committed to working towards the phasing out of animals in science. The strategy, ‘Replacing animals in science’, sets specific targets to reduce the use of dogs and non-human primates by 2030, while ensuring the UK continues to support safe and effective scientific and medical research.

The strategy is clear that while the longterm vision is to replace the use of animals in science wherever possible, some animal use remains necessary at present to develop and test new medicines, advance understanding of biology and disease, and to protect human and animal health and the environment. These activities are integral to the UK’s national health preparedness and resilience, including the ability to respond to emerging health threats. Progress towards the phasing out of animal use must therefore be scienceled and supported by reliable alternative methods.

Accordingly, the Home Office licensing regime is compatible with the strategy; it enables only tightly controlled animal use where it is scientifically justified and no suitable alternative exists.