Heathrow Airport is being targeted by protesters over claims live animals are being imported for laboratory research.
By Louise Scrivens
BBC News, London
Protestors claim thousands of animals are imported for testing
An anti-import campaign was launched in January called Gateway to Hell.
John Milton from the campaign said they will hold constant protests until the west London airport stopped allowing animals to be imported.
Gateway to Hell is the latest attempt to stop animals being used for medical research.
Police are investigating a number of recent attacks on the homes and vehicles of some airport transport executives and said it was unknown who was responsible at this stage.
Mr Milton said Manchester Airport and airport operator BAA's headquarters in London were also being targeted.
Members of the group are also involved with Stop Huntingdon Animal Cruelty (Shac) which has co-ordinated years of protests against Huntingdon Life Sciences, a medical testing company based near Cambridge.
"If we didn't think we could stop the airports we wouldn't have set up the campaign," said Mr Milton.
He claims each year thousands of mice, birds, monkeys and other animals are imported through airports to be used in medical experiments.
"We have written a few letters to BAA and have just received standard responses," he added.
A spokeswoman from BAA said the homes and vehicles of some airport transport executives had been vandalised by unknown assailants.
The spokeswoman said the incidents were part of a police investigation and it was not known who was behind the attacks at this stage.
Keith Mann, also from Gateway to Hell, said he did not categorise criminal damage as violence .
"Sabotage is a side issue compared to the violence committed against animals," he told BBC News.
"The law is changing to stop people protesting peacefully so this kind of behaviour is inevitable."
Mr Mann was sentenced to 11 years in prison in 1994 for criminal damage and attempted arson.
A spokeswoman from the Research Defence Society, which represents users of animals in experiments, said a lot of animals were bred within the UK but some had to be imported.
"The most humane way to transport animals is by air because it is the most direct way but campaigns by animal activists have meant some airlines have stopped doing it," she said.
A spokesman for the National Extremism Tactical Co-ordination Unit, a police body that monitors the animal rights movement said: "What we know at this stage is that the Gateway to Hell campaign is closely linked to Shac Stop Huntingdon Animal Cruelty.
"The group is not just targeting airports but all modes of transport which they believe is involved in transporting live animals for laboratory research.
"In relation to the damaged property these incidents are being investigated by various police forces but at this stage are not being linked to the Gateway to Hell campaign.
"Protests have been held at Heathrow and our role is to advise police on how to handle these situations."
Mr Mann said a large protest was planned in Dover to mark World Laboratory Day on 30 April.