Has anyone any suggestions regarding swallows nesting and entering the factory, they are quite persistent. We have tried such deterrents as silver streamers and electronic bird noise sounders which do work for a while until the birds get used to them.

Contact the RSPB if they have chicks. Otherwise proofing of the building, and consider the use of decoys alongside the sounders? The other half is pest controller I can ask him for further info perhaps?

Removal and/or destruction of the nests is illegal. Enforcement depends upon someone noticing and reporting the offence. Few do. Enforcement is therefore low. Locally, a building company is, at this moment, destroying a couple of acres of wood/brush-land. They have taken what they call "reasonable steps" to ensure no destruction/disturbance. That's it. The aforementioned RSPB admit that as long as they are not willfully destroying the nests then no action is possible.