SIR–When this government came to power it pledged to reduce the number of animals used in vivisection. But the number of animal experiments in 2013 was the highest in nearly 30 years.

There is an attempt to conceal the bad news by suggesting that the exponential increase in the use of genetically modified (GM) animals does not somehow represent animal suffering.

But, as Animal Aid’s detailed investigations have shown, GM animals are subjected to some of the most horrific torments imaginable.

And yet there are so many non-animal, human-relevant research methods, such as the use of human cells and tissues, computer modelling and studies on human volunteers.

Biomedical researchers have a duty to embrace such methods wholeheartedly, so that animals can be saved from the pain and misery of the laboratory, and human medicine can stand a genuine chance of progress.

Isobel Hutchinson, Animal Aid, The Old Chapel, Bradford Street, Tonbridge, Kent