Question to the Home Office:

To ask the Secretary of State for the Home Department, what estimate she has made of the number of animals involved in LD50 tests by type of animal; and what assessment she has made of the effectiveness of those tests.

The Home Office publishes detailed annual statistics on the use of animals in science, including procedures for acute and sub-toxicity testing methods such as LD50 (Lethal Dose 50) and LC50 (Lethal Concentration 50). According to the latest published figures for 2024, there were 11,992 procedures in this category, and the statistics include a breakdown by species.

All testing using protected animals, including the LD50 and LC50 tests, are subject to strict regulation under the Animals (Scientific Procedures) Act 1986.

These particular tests are internationally recognised methods for assessing toxicity and are required under guidelines set by the Organisation for Economic Co-operation and Development (OECD) and the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) regulations overseen by the Department for Environment, Food & Rural Affairs. Some authorised medicines in the UK necessitate quality control tests which require the use of animals, conducted to ensure the quality, safety, and efficacy of specific medicines. The Government is committed to non-animal alternatives in science and has published a strategy to support their development, validation and adoption. The strategy is available at:

https://www.gov.uk/government/publications/replacing-animals-in-science-strategy/replacing-animals-in-science-a-strategy-to-support-the-development-validation-and-uptake-of-alternative-methods