August 2026 marked 150 years since the UK Parliament passed the Cruelty to Animals Act 1876, a landmark piece of legislation making the UK the first country in the world to enforce specific restrictions and regulations on the use of animals for research.

This anniversary provides the perfect opportunity to reflect on how the legal approach to animal use in science has evolved in the UK over the last 150 years, and what we should be considering in the future.

Cruelty to Animals Act 1876

In 1875, the Government set up a ‘Royal Commission on Vivisection’ (a form of public enquiry), following intense public opposition to animal testing. The Commission recommended that legislation be introduced to control animal testing, leading to The Cruelty to Animals Act, which was enacted into UK law on 15^th August 1876.

The Act made it an offence to perform experiments on living animals that would cause pain, unless for the purpose of advancing physiological knowledge, saving or prolonging life, or alleviating suffering. It covered only vertebrates, and outlined other provisions including:

• Only allowing scientists to perform experiments
• Requiring licences before experiments were permitted
• Ensuring that animals were anaesthetised before use and used only once
• Requiring that animals must be killed once their use in a study was over

Despite being the only piece of legislation regulating animal research in the world, it faced criticism from animal rights campaigners, with many stating that it lacked provisions for public accountability, particularly around the licensing procedures.

Animals (Scientific Procedures) Act 1986

The Cruelty to Animals Act stood alone in regulating animal use for science until 1986. 110 years after its introduction, it was replaced by the Animals (Scientific Procedures) Act (ASPA), which remains in place to this day.

ASPA regulates the use of protected animals in scientific, educational, or any other experimental procedures that may cause pain, suffering, distress or lasting harm. Protected animals include any living vertebrate other than humans, and as of 2013, any living cephalopod (octopus, squid, or cuttlefish).

Similarly to the Cruelty to Animals Act, ASPA also outlines a licensing system. ASPA requires three licences to be held before work on animals can commence:

• An establishment licence for any place where work is conducted using animals
• A personal licence for each person conducting regulated procedures on animals
• A project licence for the programme of work being conducted

One significant difference between the two Acts was the inclusion of the 3Rs into ASPA, making the Replacement, the Reduction and the Refinement of the use of animals in science a legal requirement. The inclusion of the 3Rs into ASPA signified a shift from solely regulating animal experiments, to improving welfare standards and minimising animal use alongside those regulations. Particularly with Replacement being the priority of the 3Rs, it meant that animals should not be used if an alternative method exists. However, we do know that this isn’t always the case.

The Replacement issue

If you’ve come across our work before, you might be aware that it predominantly focuses on improving the legal implementation of Replacement. That’s because there is evidence that Replacement is not always robustly fulfilled.

Back in 2023, we saw the publication of Dr Francis Rawle’s report ‘The Role of Review and Regulatory Approvals Processes for Animal Research in Supporting Implementation of the 3Rs.’ This report was based on interviews and surveys with stakeholders within the animal research community, including Animal Welfare and Ethical Review Body (AWERB) members, Establishment Licence holders, Named people (such as Veterinary Surgeons), the Animals in Science Regulation Unit (ASRU) inspectors of the Home Office, Animals in Science Committee members, and funding reviewers. Among other important findings, the report identified that “replacement does not seem to be covered well by any of the review processes. AWERBs and ASRU Inspectors rarely suggest use of replacements.”

This report was incredibly important to the sector, as it stated in black and white that there is an issue with Replacement, which must be addressed if ASPA is to fulfil what it is set out to achieve.

More broadly, it highlighted a growing recognition that, while the UK has legislation requiring the consideration of alternatives to animal use, stronger action is needed to ensure that Replacement is consistently embedded throughout the research system. And with that, we fast forward to November 2025.

Government strategies

In November 2025, following a manifesto commitment to phase-out animal testing, the Government published its ‘Replacing Animals in Science’ strategy, to support the development, validation and uptake of alternative methods.

The strategy sets out a long-term vision of ‘a world where the use of animals in science is eliminated in all but exceptional circumstances, achieved by creating a research and innovation system that replaces animals with alternative methods wherever possible.’ This was accompanied by a range of commitments to achieve this goal.

Some of these commitments involve strengthening the requirements and frameworks of ASPA such as:

• Strengthening training provisions and guidance around Replacement for funders, reviewers, and early career researchers
• Implementing the Rawle Report recommendations
• Reviewing how the collection and publication of additional statistics can lead to further replacement opportunities

Looking forward

These commitments, as well as the wider strategy, represent an important shift. The point isn’t just that Replacement is a legal requirement, it is about looking at whether the systems and processes surrounding animal research are actually delivering it. The Government’s strategy commitments focus on effective implementation, which requires the right incentives, training, oversight, data and accountability across the research system.

This is where our work at Replacing Animal Research comes in. Our work across policy research and education focuses on the gap between what the law requires and what happens in practice. If the UK is serious about its ambition to replace animals in science, Replacement must be treated as a meaningful and robust requirement, rather than simply a legal principle to be considered, often too late in the process. This is why we have developed resources such as our ‘Policymakers Guide to Replacing Animal Research’, and our Replacement Checklist for those in the research system.

The legislative journey from the 1876 Cruelty to Animals Act, through ASPA, and then to the Government’s 2025 strategy shows a clear direction of travel towards reducing and ultimately replacing the use of animals in science wherever possible. The challenge now is making sure that ambition translates into meaningful change.

At Replacing Animal Research, we will continue to focus on supporting stronger implementation of Replacement, scrutinising how the current system operates, and advocating for the changes needed to secure a future of non-animal science.