Contractors refuse to work on projects unrelated to laboratories as ALF issues new threat to Oxford project.

Construction firms are avoiding projects across the pharmaceutical sector because of the fear of action by animal rights extremists.

Pharmaceutical trade body the Association for the British Pharmaceutical Industry has revealed that some construction firms are refusing to undertake ordinary building work unrelated to laboratory projects.

The revelation comes as a Building investigation has revealed that threats to the wider construction industry have escalated. Meanwhile, the Animal Liberation Front has renewed warnings that the contractor on the Oxford animal research laboratory would be targeted in "the same way as Montpellier".

Montpellier, the original contractor, left the project in 2004 after letters were sent to its directors threatening to expose them as sex offenders.

A spokesperson for the ABPI said: "We are well aware of capitulations resulting from actions by animal rights activists. Companies are not agreeing to work with organisations even distantly involved in animal research, which means virtually the entire pharmaceutical sector. These companies very much include those from the building sector."

The ABPI spokesperson said that last year 103 companies from across all industries had said they would not work with firms from the sector even distantly connected to animal research. He would not reveal how many of these firms were from the building sector.

A senior director of one construction firm, whose clients include pharmaceutical multinational Johnson & Johnson, said that the threat of exposure to rights activists was forcing his and other firms to reconsider their work for the sector.

He said: "Obviously it's a very good source of business for us, which we don't want to lose - but there comes a point, if there is enough aggression, where it becomes a consideration. We are reviewing the situation on an ongoing basis, and there is obviously uncertainty there."

The DTI confirmed this week that prime minister Tony Blair was in talks with industry leaders over animal rights extremism, as revealed in Building last week.

A spokesperson said: "A meeting took place between the prime minister and representatives from industry and finance to discuss animal rights extremism before Christmas. The government continues to reiterate its support for those standing up to extremism."