Company Index
- O Rings Ltd - Chichester
- Oadby Plastics Ltd - Warrington
- Oak Tree Plastic and Engineering Ltd - West Bromwich
- Oaklands Plastics Ltd - Coleshill
- Oasis Leisure Products Ltd - Doncaster
- Ocean Endeavours Ltd - Verwood
- Ocean Manufacturing Ltd - Cork
- Ocean Mouldings - Bridgwater
- OF Bell and Co - Bishop Auckland
- Ogle Models and Prototypes Ltd - Letchworth
- OGM Ltd - Witney
- OKW Enclosures Ltd - Fareham
- Oldrati Ltd - Slough
- Oleotec Ltd - Ellesmere Port
- Olympic Trade Frames - Skegness
- OMA (UK) Ltd - Congleton
- Omega Design and Development Ltd - Wolverhampton
- Omega Plastics - Blyth
- Omnikote Ltd - Aylesbury
- OMS (UK) Ltd - Stockport
- On Course Matting - Oswestry
- Op Plastics - Shifnal
- Opella Ltd - Hereford
- OPPM Ltd - Ilkeston
- Optical Coating Technologies Ltd - Tamworth
- Opticron - Gillingham
- Orapi Ltd - Bradford
- Organic Specialities (A division of Thomas Swan and Co Ltd) - Leicester
- Orion Trent Insulations Ltd - Burton on Trent
- Orion Trent Insulations Ltd - High Wycombe
- Orkot Marine Bearings - Rotherham
- Osmor Products Ltd - Hassocks
- Osprey Ltd - Church Stretton
- Osprey Ltd - Scarborough
- OTR Tyres Ltd - Alfreton
- Outshine Windows - Abergavenny
- Oversolve Ltd - Nottingham
- Owen Mumford Ltd - Chipping Norton
- Owen Mumford Ltd - Oxford
- Oxford Plastics Systems Ltd - Chipping Norton
- Oxplas Ltd - Princes Risborough
