In my previous role as a teacher and working in animal welfare education, I often found myself discussing the boundaries of the animal kingdom with students. Outside of the laboratory, it is simple, animals are animals. But inside the world of scientific research and testing, boundaries around what an ‘animal’ is in regulated research are defined by a piece of legislation known as the Animals (Scientific Procedures) Act 1986 or ASPA. 

ASPA covers many, but not all animal species. ASPA currently regulates the use of  ‘living vertebrates’ including specific stages of foetal development, and cephalopods like octopuses, squid and cuttlefish. When it was drafted forty years ago, this boundary was based on the scientific understanding of sentience at the time – the capacity of a creature to experience feelings such as pain, suffering, and distress. But science doesn’t stand still. Over the last few decades, our understanding of animal sentience has evolved. In 1993 the common octopus was added to the Act, followed by an update in 2012 to include all living cephalopods.  

In a country where our Government is openly working to phase out animal use in science, with a Replacing Animals in Science Strategy being published last year, it is essential that ASPA has the teeth to support this. This outdated legislation must continue to evolve. 

This brings us to a fundamental legal and ethical concept that we believe should be guiding our regulatory framework and decisions, but sadly isn’t: the precautionary principle. 

Using the Precautionary Principle to protect animals in science

The precautionary principle is a core framework in risk management sometimes used in law, for, example EU environmental regulations, which states that if an action or policy has a suspected risk of causing severe harm, the burden of proof falls on showing it does not cause harm, rather than waiting for absolute scientific certainty before taking protective action. 

In the context of animal research, it would mean that if there is compelling evidence that a species can suffer, we should err on the side of caution and grant them legal protection immediately, rather than waiting for absolute, undeniable proof while millions of sentient creatures continue to undergo procedures without regulatory oversight. In a world where animal research is still happening this unquestionably is a sensible, approach to protecting animals and advancing legislation to do this. 

Unfortunately today, for some animals, EVEN WITH scientific evidence of sentience, the legal protection of ASPA remains glaringly absent.  

Delays in protection for crabs and other decapod

We saw a major milestone when the Animal Welfare (Sentience) Act 2022 was introduced and explicitly recognised decapod crustacean, such as crabs, lobsters, and prawn, as sentient beings, heavily backed by a rigorous independent review from the London School of Economics (LSE). The LSE report concluded in 2021 there is robust scientific evidence of sentience in these animals. 

Yet, four years after this legal recognition, a glaring paradox remains. Decapods are now recognised as sentient, but they are still completely excluded from ASPA. They have the legal status of sentience, but zero protection in the lab. 

 Decapods are now the only animals classified as sentient in the UK that are not included in ASPA. This is not good enough. 

A phased approach is not good enough

In March 2026, the Animals in Science Regulation Unit (ASRU) indicated that the Home Office Minister Lord Hanson had agreed to a ‘phased approach’ to policy development regarding decapods. Whilst this is a positive step in terms of recognition that the Government doing something, there has as yet been no more detail. The focus has shifted to the development of a ‘roadmap’  to build an ‘evidence base’ focusing on ‘sector readiness’ and preparatory non-legislative activities such as voluntary reporting, targeted training and advice, and adopting baseline industry-led welfare standards.  

The full inclusion of decapod crustaceans as a ‘protected animal’ is explicitly described as a ‘future consideration’ rather than a certainty. We need more information. 

The Government has had four, in reality five years to conduct preparatory work since the publication of the LSE report. They should be further ahead. 

While a phased approach sounds measured, it essentially treats the inclusion of decapods under ASPA as an optional exploration rather than a necessary conclusion. Voluntary standards and industry-led guidelines do not carry the weight of law. They do not require the rigorous scrutiny of Project Licences, nor do they legally mandate the exploration of non-animal alternatives before procedures are carried out. 

In light of the LSE report and the 2022 Act, these animals should be given the same protections extended to cephalopods in previous years. 

This delay demonstrates a disregard for scientific evidence, animal welfare and undermines the principles of the Animal Welfare (Sentience) Act 2022 and statutory purpose of ASPA to protect animals.  

ASPA needs to be more

At Replacing Animal Research, we advocate for the replacement of all animals in research. We believe incorporating the Precautionary Principle into law to help protect animals in research is an inevitable and essential advancement of the legislation. If we truly want to phase our or replace animal use, at some point we have to consider removing boundaries around what animals are or are not protected in scientific research. When the average person on the street hears ‘Animals in Scientific Procedures Act’ they may assume the law is working for all animals. But it isn’t. 

If the inclusion of the precautionary principle is not happening now, at the VERY minimum the law should  be defaulting to the scientific evidence. This is not 1986. The legislation needs to reflect the scientific evidence and values of 2026.  

What next?

If the Government is truly committed to Replacement and phasing out animal testing, it must stop kicking the can down the road. We need immediate action and firm, transparent timelines regarding the promised roadmap with an imminent deadline for including decapod crustaceans in the law. We would like to see the Government working closely with organisations such as Crustacean Compassion that already have working knowledge of how these animals are currently used in science. 

More importantly, we need ASPA to continue to evolve and expand its boundaries. Protecting animals based on convenience rather than scientific evidence of sentience undermines the very integrity of UK science policy. ASPA needs to do more, and be more, for all animals.