Every year the Home Office releases the statistics on animal research in Great Britain (Northern Ireland released separately) for the preceding year. In 2015, the total number of procedures on animals was 4.14 million, up 7% from the 3.87 million in 2014. However the UK Home Office has warned that quality issues with the 2014 data (the first year under a new counting methodology) means it is likely that the 2014 numbers were under-reported.
The total number of animals was slightly lower, at 4.07 million, as some animals were used for more than one procedure*. In 1987 the UK changed the way in which it counted animals, from the total number of animals to the total number of procedures.The statistics for Northern Ireland are not included and are published separately here (19,857 procedures in 2014).
*The total number of animals excludes those animals first used in a previous year, which underwent a procedure in the current year, in order to prevent double counting of animals between years.
The last few years has seen the number of Genetically Altered animals (mainly GA mice) being bred rising as a proportion of all studies; this accounts for 50% of all procedures (in 2014).
We can clearly see that rodents are the majority of animals used in Great Britain. Overall, mice, rats, birds and fish account for over 96% of all animals used.
As we can see, mice, rats, birds and fish account for over 96% of all procedures on animals in Great Britain. Dogs and cats account for 0.12% and primates account for around 0.09%. Invertebrates such as fruit flies and nematode worms are widely used by researchers but are not covered by the Animals (Scientific Procedures) Act and are thus not included. The only invertebrate included in the statistics are cephalapods, though none were used in 2015.
When we look at the other uses of animals in the UK we see that those killed for medical research (and the huge benefits that go with it) are far outweighed by the numbers of fish and chickens eaten, and even by the number of birds and other wildlife killed by domestic cats.
Finally, it is worth remembering the huge benefits brought about by animal research. Here are some (approximate) annual figures of treatment used that were developed through animal research.
Home Office 2014 reports: https://www.gov.uk/government/statistics/statistics-of-scientific-procedures-on-living-animals-great-britain-2015