A laboratory in Potters Bar has defended its use of animal testing, claiming it is a “crucial” part of the work it does to protect public health.

More than 50 campaigners from the Anti Vivisection Coalition (AVC) gathered outside the National Institute for Biological Standards and Control (NIBSC), in Blanche Lane, on Saturday to demonstrate against its “evil” experimentation on monkeys.

The protesters argued the lab is not producing new life-saving drugs but is still testing old drugs on animals while more advanced testing methods are available.

But a NIBSC spokesman said its work is vital to public health, and the animals it uses are kept in “excellent conditions” and are “extremely well looked after”.

He said: “NIBSC has done more than any other laboratory in the world to reduce the dependence on animals for medicines testing and is an international leader in developing alternatives to Replace, Reduce and Refine animal testing, known as the three Rs.

“Our animal work is a crucial part of the work we do to protect public health - for example to help us carry out independent safety testing of vaccines that all our children receive or in the fight to eliminate HIV.

“Every batch of the routine vaccine against diphtheria, whooping cough, HiB, tetanus and polio that all UK children receive in the first few months of their lives is independently checked at NIBSC to make sure it is going to be as safe and effective as possible.”

He went on to say that the NIBSC is regularly called on to help deal with incidents and emergencies, including the influenza pandemic in 2009 when it helped develop candidate vaccine strains and measurement standards.