Sir, Sarah Brown says that advocates of animal testing deceive the public with their unsubstantiated claims (Letters, April 7). The Advertising Standards Authority agrees: they recently ruled that the claim "Some of the major advances in the last century would have been impossible without animal research" is misleading and should not be repeated. Yet this is the very mantra of Pro-test supporters, who repeat it constantly.

This issue must be judged on facts. Take drug testing: the evidence to date shows that animal tests predict fewer side-effects than a coin toss. This is why nine out of ten of drugs that pass animal tests fail in human trials.

Six unfortunate men were reassured that TGN1412 was safe because it was safe in monkeys. Withdrawn arthritis drug Vioxx caused many thousands of fatal heart attacks, after animal tests predicted it would be good for the heart.

Patient safety group Europeans for Medical Progress supported by 83 per cent of GPs and 218 MPs suggests a scientific evaluation of animal testing to settle this matter once and for all: see www.curedisease.net The truth is that superior human-based tests would have predicted the effects of both TGN1412 and Vioxx, where animal tests failed so tragically.

Kathy Archibald, Director, Europeans for Medical Progress