| O2 Store - Telecommunications |
| Oasis Stores PLC - Retail sale of clothing |
| Oddbins Ltd - Retail sale of alcoholic and other beverages |
| Oddbins Ltd - Retail sale of alcoholic and other beverages |
| Oddbins Ltd - Retail sale of alcoholic and other beverages |
| Office Angels - Labour recruitment and provision of personnel |
| Old Deer Park - Operation of sports arenas and stadiums |
| Old Deer Park - Letting of own property |
| Old Vicarage School - General secondary education |
| O'Neill's Irish Bar - Bar |
| OnlineAdNetwork - Business and management consultancy activities |
| Oracle Corporation (UK) Ltd - Software consultancy and supply |
| Orad Hi-Tech Systems - Radio and television activities |
| Orange Tree Theatre Ltd - Artistic and literary creation and interpretation |
| Orchard Events Ltd - Other business activities not elsewhere classified |
| Organic World - Retail sale of meat and meat products |
| Origin Asia - Restaurant |
| Origin Brand Consultants Ltd - Business and management consultancy activities |
| Originata Ltd - Other building completion |
| Oscar Pet Foods - Manufacture of prepared pet foods |
| Our Lady Queen Of Peace - Activities of religious organisations |
| OutlookSoft - Software consultancy and supply |
| Owen Smith - Photographic activities |
| Oxfam - Social work activities without accommodation |
| O Widman & Co Ltd - Manufacture of paper stationery |
| Orthodontic Practice - Orthodontist |
| Office Angels - Employment Agency |
| Omstar Filling Station - Petrol Filling Stations |
| Oceanwide Ltd - Activities Not Ascertained |
| Oscar Petfoods - Pet Foods And Animal Feeds Retailers |