The website urges supporters to target Deloitte and Touche

HLS, based in Cambridgeshire and Suffolk, uses live animals to test pharmaceuticals and chemicals.

Stop Huntingdon Animal Cruelty group (Shac) is stongly opposed to the work and wants all companies to cut their links with the firm.

On its website, Shac calls for action against auditors Deloitte and Touche, which the group describes as a "brilliant target".

So far the new campaign seems to be focusing on senior managers and secretaries in the company's HLS team.

E-mail warnings

Workers say they have received letters, e-mails and telephone calls from the protesters warning them against involvement with HLS.

Shac said it would occupy Deloitte premises and stage demonstrations outside offices and managers' homes.

Deloitte and Touch and HLS both say they are taking the campaign very seriously and are disappointed that a legitimate company can be targeted in this way.

Last year Shac targeted an insurance company which the group claimed had links with HLS.