O
- O & C Holdsworth Ltd., HALIFAX, United Kingdom
- O & H Capital Ltd., LONDON, United Kingdom
- O & H Construction Ltd., LONDON, United Kingdom
- O & K Orenstein & Koppel Ltd., NORTHAMPTON, United Kingdom
- O & S Gear & Engineering Ltd., ATHERSTONE, United Kingdom
- O 2 Ltd., SLOUGH, United Kingdom
- O A O Technology Solutions UK Ltd., STRATFORD-UPON-AVON, United Kingdom
- O A Taylor & Sons Bulbs Ltd., SPALDING, United Kingdom
- O A Taylor & Sons Ltd., SPALDING, United Kingdom
- O B C Insurance Consultants Ltd., SOLIHULL, United Kingdom
- O C & C, LONDON, United Kingdom
- O C C Europe Ltd., LONDON, United Kingdom
- O C O Ltd., DARTFORD, United Kingdom
- O C S Access, DARTFORD, United Kingdom
- O C S Consulting Plc, BOREHAMWOOD, United Kingdom
- O C Summers Ltd., HUNTINGDON, United Kingdom
- O D Systems Ltd., MANCHESTER, United Kingdom
- O E F D Ltd., LONDON, United Kingdom
- O E Group Ltd., STONE, United Kingdom
- O E P Furniture Group Plc, WALTHAM ABBEY, United Kingdom
