- AECOM Design Build Limited
- Amec Group Limited
- Anglian Water Services
- Balfour Beatty Services
- Birse Civils Limited
- British Energy Generation Limited
- British Rail
- Conamar Building Services Limited
- Crummock (Scotland) Limited
- Devon County Council
- EDF Energy
- Elliott Group UK
- Hanson Group
- Interserve Construction Limited
- Keltruck Limited
- Lain O’Rourke Infrastructure Limited
- Metabrasive Limited
- M J S Express Limited
- M W H Treatment Limited
- RAF
- RMLS Limited
- Scottish Water
- Speedwell Honda
- Spirax Sarco Limited
- Waco UK Limited
- Walker Construction (UK) Limited
- Wernick Construction Limited
- Yorkshire Water
