Scientific testing on live animals has fallen to its lowest level since 2010, official figures show.

Researchers carried out 3.79 million procedures on living animals in England, Scotland and Wales last year, a decrease of 4% from 2016 and the smallest number for eight years.

However the number is up 4% from a decade ago, the data from the Home Office reveals.

Horses were involved in 10,600 experiments in 2017, an increase of almost a fifth (18%) from the previous year when there were 8,948.

A horse
Horses were involved in 10,600 experiments in 2017 (Simon Cooper/PA)

The Home Office said this was “principally for the provision of blood products for diagnostic products”.

Professor Dominic Wells, chairman of the animal sciences group at the Royal Society of Biology, said the same horse may have been used multiple times for different procedures.

“The number of horses used for the first time in 2017 is reduced compared to 2016, but the number of procedures has gone up, and that’s because some of these horses are used as essentially blood donors,” he said.

Animal rights groups said the overall decrease was “too little, too late” and called for greater investment in scientific methods which do not involve testing on living creatures.

Hazel Jackson, science director of Animal Free Research UK, said: “This almost negligible decrease in the number of animal experiments is simply too little, too late.

“Instead of continuing to pump money into outdated, cruel and often misleading animal research, more needs to be done to invest in the UK’s expert researchers who are developing innovative, human-relevant methods which are best placed to discover treatments for debilitating human diseases.”

Around half of the total procedures were experiments using animals to develop treatments, test the safety of pharmaceuticals and chemicals, for surgical training and education, and for species protection.

The remainder involved the creation and breeding of genetically modified animals, producing offspring for use in further experiments.

Mice, rats and fish accounted for 87% of experimental procedures.

The number involving mice fell by 10% from 1.22 million in 2016 to 1.09 million in 2017, while those with rats decreased by 2%.

However there was an 8% rise in use of fish, from 287,000 in 2016 to 308,000 last year.

This was mainly due to the use of genetically modified zebrafish in basic research, according to the statistical release.

Cats, dogs, horses and non-human primates – described as “specially protected species” – were used in 1% of experimental procedures last year.

The number of experiments with dogs fell by 22% from 4,932 in 2016 to 3,847 in 2017, while those with cats rose slightly from 190 to 198.

Since 2014, the Home Office, which is responsible for regulating animal experiments, has classified testing according to the amount of suffering it causes.

Of around 1.89 million animal experiments performed last year, 50% were assessed as mild, 26% as moderate and 5% as severe.

Cruelty Free International said it was concerned that Britain’s departure from the European Union may lead to an increase in animal testing, with the UK potentially having to duplicate some tests.

Chief executive Michelle Thew said: “Brexit has the potential to be a real opportunity to demonstrate to the world that the UK is committed to making difference for animals by reducing the extent of suffering in our laboratories and replacing animals with modern, humane testing methods.

“The UK Government needs to step up and use this moment in history as a springboard to step up efforts to stop unnecessary animal experiments.”