Animal rights activists gathered for a candlelit vigil outside the National Institute for Medical Research in Mill Hill on Monday to mark the 4th international animal rights day.

"We have tried all the legal channels and they don't work," said 'Pam', an activist, who prefers not to give her real name. "If we can't get anywhere by democratic means then what alternative do we have?"

The NIMR claims animal experiments are an integral part of its work researching diseases such as TB, malaria and infertility. It says animals do not suffer unnecessarily and every year it receives millions of pounds in government funding and fees from commercial companies and the European Union.

'Pam' remained skeptical about the industry's willingness to reform itself. "Vivisection is quite a complicated business that involves a lot of money and is big business for breeders. I don't think they want alternatives," she said.

'Joanna', a student who has travelled from outside London to protest in Mill Hill, said: "I do think that changes will happen though, because more people are beginning to realise just how fraudulent animal research is."

'Guy', who has been protesting regularly at the institute for two years, said: "Animal acivists have received a bad press and are often branded as violent. However, people should realise that these are only a few extremists.

"You want to know about violence then you should ask the institute to let you in. What goes on in there, that's legal violence."

The NIMR declined to comment on the protest.