The UK government acted unlawfully in assigning a ‘moderate’ severity rating to a licence for invasive brain surgery on marmosets performed at a Cambridge University neuroscience laboratory, a High Court judge ruled last week.

The verdict partially vindicated the British Union for the Abolition of Vivisection (BUAV), which had sought and secured a judicial review of the government’s licensing procedures for animal research following a 10-month undercover investigation at the Cambridge laboratory during 2000/2001.

Mr Justice Mitting rejected further allegations by the BUAV that the Home Office had neglected its legal duty to ensure animal suffering was minimised in relation to the pre- and post-operative care arrangements for the marmosets used in the experiments. He also granted the government leave to appeal against the ruling in the BUAV’s favour.

Nonetheless, the campaign group claimed the decision should result in more licences for animal research being turned down, since experiments properly categorised as meriting a ‘substantial’ severity rating would not pass the Home Office’s cost (to the animal)/benefit (to research) test for animal procedures.

“It is also likely to mean that the percentage of licences categorised as ‘substantial’ will be perhaps considerably higher, and therefore offer the public a more accurate picture of the extent of animal suffering that goes on in UK government-licensed experiments,” the BUAV added. The proportion of animal experiments classified as causing ‘substantial’ suffering has remained static at 2% in the government’s annual statistics ever since these data were made available in 1998, it noted.

Severity limit

Under the Animal (Scientific Procedures) Act 1986, the Home Office assigns a severity limit to each protocol in a research proposal. This represents “the worst potential outcome for any animal subjected to the protocol, even if it may only be experienced by a small number of the animals to be used”, the Home Office explains.

The categories used are ‘unclassified’, ‘mild’, ‘moderate’ or ‘substantial’. According to Home Office guidance, the ‘moderate’ severity rating includes toxicity tests without lethal endpoints and “many surgical procedures (provided that suffering is controlled and minimised by effective post-operative analgesia and care)”. Protocols with potential to cause greater suffering may also fit into this category if they include controls minimising severity or terminating the protocol before the animal shows more than moderate adverse effects.

A ‘substantial’ severity limit applies to a procedure – including “major” surgery – that “may result in a major departure from the animal’s usual state of health or well-being”. If the expectation is that even one animal would suffer substantial effects, the procedure would merit a ‘substantial’ limit, the Home Office notes.

Licence holders should “approach the limit of severity which has been authorised only when absolutely necessary to meet the specified objective”, the guidance says. Nonetheless, licence holders may be able to obtain temporary clearance for a higher limit where necessary, provided the Home Office is notified promptly and “sufficient justification” is shown.

The Home Office also allocates a severity band to the whole project under review, reflecting the cumulative effect of each procedure and the “overall level of cumulative suffering to be experienced by each animal”. This assessment is used by the Home Secretary to weigh up “the likely adverse effects on all the animals to be used against the benefits likely to accrue”, as required by the 1986 Act.

The BUAV challenged the ‘moderate’ severity banding assigned by the government to experiments that included removing the tops of marmosets’ heads to induce stroke. Mr Justice Mitting found the expert advice provided to the Home Office had understated the extent of the “pain, suffering, distress or lasting harm” that could be experienced by the animals.

More subjective

According to the Financial Times, the judge also agreed with the BUAV that the Home Office should use more subjective terms in tune with public opinion – a position described by Professor Colin Blakemore, chief executive of the Medical Research Council, as “very worrying”.

The Home Office issued a statement expressing its disappointment with the verdict and its belief that officials have been “rigorous in applying the strict criteria of the Animals (Scientific Procedures) Act 1986”.