The unions South West branch is handing out the leaflets at Cromwell Press, which produces academic and religious books.

Peter Harris, a GPMU industrial officer, said the management appeared to be hostile and the union was keeping its activities outside the building in Trowbridge.

"Theres been correspondence from the company to the GPMU complaining about the activities," said Harris.

A local newspaper report said police were called after scenes of bullying. But Harris denied there was bullying: "We have simply responded to employees wishing to seek membership. We would prefer to talk to members and get facilities within the building."

Neither Gavin Brooks, the South West branch organiser dealing with Cromwell Press, nor Allan Hicks, the firms director, could be contacted.