| NSE Consulting Limited | Professional & scientific | 2008 |
| Nu-Beau Ltd | Other services | 2018 |
| Number One Mortgages Ltd | Financial services | 2004 |
| Nurse Expert Witness Limited | Professional & scientific | 2013 |
| NV Heating Ltd | Construction | 2021 |
| Nxtgen Management Ltd | Arts & recreation | 2014 |
| O.M.K. Design Limited | Manufacturing | 1964 |
| Oakmile Limited | Real estate | 1993 |
| Oatopia Ltd | Hospitality | 2014 |
| OC73 RTM Company Limited | Extraterritorial | 2024 |
| Ocean SET Ltd | Arts & recreation | 2018 |
| Ocean View Projects Ltd | Construction | 2025 |
| Odous Dental Limited | Other services | 2015 |
| OFC Land Ltd | Real estate | 2011 |
| OIL Facilities Management Limited | Households | 2015 |
| Oleveaskincare Limited | Wholesale & retail | 2025 |
| Omega Oxygen Ltd | Wholesale & retail | 2018 |
| ON Infinity Ltd | Information & communication | 2022 |
| ON Line Systems (Maintenance) Limited | Information & communication | 1998 |
| ON Line Systems (Northern) Limited | Information & communication | 1992 |
| ON Line Systems Midco Limited | Professional & scientific | 2022 |
| One MAN Band Design Ltd | Professional & scientific | 2011 |
| One Step Mortgages Limited | Financial services | 2020 |
| Online Bite Ltd | Information & communication | 2017 |
| Online Video Solutions Ltd | Administrative & support | 2007 |
| Open Interface Limited | Information & communication | 2025 |
| Optinit Ltd | Information & communication | 2007 |
| Opus Build Ltd | Manufacturing | 2026 |
| Orchard PM Limited | Real estate | 2020 |
| Original Allstars Music C.I.C. | Information & communication | 2012 |
| Original Artists Music Limited | Information & communication | 1989 |
| Orio Electrical Services Ltd | Construction | 2023 |
| Osbourne Villas Freehold Ltd | Real estate | 2024 |
| OUT to Sea Ltd | Professional & scientific | 2012 |
| P&J S Properties Ltd | Real estate | 2020 |
| P. S. C. Associates Limited | Professional & scientific | 2008 |
| P.P.Fencing (Brighton) Ltd | Construction | 2026 |
| PAD Landscape Ltd | Extraterritorial | 2023 |
| Paja Ltd | Hospitality | 2018 |
| Paladone Newco Limited | Financial services | 2023 |
| Paladone Products Limited | Wholesale & retail | 1994 |
| Paladone USD SPV Limited | Financial services | 2023 |
| Palate Bottle Shop Ltd | Wholesale & retail | 2020 |
| Parastudio Ltd | Professional & scientific | 2019 |
| Parasure Organics Limited | Manufacturing | 2025 |
| Park Royal Brighton Limited | Households | 2012 |
| Parka Digital Ltd | Information & communication | 2023 |
| Part Time FD Limited | Professional & scientific | 2002 |
| Pass With Pearson Ltd | Administrative & support | 2023 |
| Paula Sargent Education Limited | Education | 2016 |
| Pavx Ltd | Construction | 2025 |
| Peakshop Sales Ltd | Wholesale & retail | 2024 |
| Pedas Pedis Limited | Wholesale & retail | 2022 |
| Peirce Aviation Services Ltd | Professional & scientific | 2018 |
| Pelham Transport Consulting Ltd | Professional & scientific | 2012 |
| Pelvic Health Coach International Ltd | Health & social care | 2026 |
| Pengstone Ltd | Professional & scientific | 2025 |
| Penguin Healthcare Ltd | Health & social care | 2024 |
| Pens & Hammers Limited | Information & communication | 2021 |
| Peter's Parcels Ltd | Transport & logistics | 2026 |
| Petrel Pioneer Limited | Financial services | 2024 |
| Phil Allen Design Ltd | Administrative & support | 2018 |
| Phoenix Blue Consulting Limited | Administrative & support | 2025 |
| Phylmaur 10 Limited | Real estate | 2013 |
| Pied Piper Activities Limited | Arts & recreation | 1997 |
| Pigs in Flight Limited | Information & communication | 2018 |
| Pinda Properties Limited | Real estate | 1960 |
| Pinnacle Communications Limited | Information & communication | 1999 |
| Pinnervale Investments Limited | Real estate | 2005 |
| Pioneer Safety Group Limited | Financial services | 2023 |
| Pitchara Ltd | Information & communication | 2026 |
| Plumbmech Sussex Ltd | Construction | 2021 |
| PO & a Limited | Information & communication | 2017 |
| Poethurst Limited | Professional & scientific | 1982 |
| Popular Watch Company Ltd | Manufacturing | 2024 |
| Portas AV Limited | Extraterritorial | 2011 |
| Power Brains Limited | Information & communication | 2025 |
| Power Planning Associates Limited | Professional & scientific | 1997 |
| Powerwatts UK Limited | Arts & recreation | 2017 |
| Precision Metal Products Limited | Manufacturing | 1982 |
| Premier Chain Ltd | Professional & scientific | 2021 |
| Presh-Eat Ltd | Wholesale & retail | 2022 |
| Prestige Wealth Planning Limited | Financial services | 2005 |
| Prestonville Court (Brighton) Limited | Households | 1987 |
| Prima Block a Ltd | Real estate | 2025 |
| Prima Block Ltd | Real estate | 2020 |
| Prime Decor (South Coast) Limited | Construction | 2019 |
| Princes Court Hove (Management) Limited | Households | 2004 |
| Prism Business Developments Limited | Information & communication | 2001 |
| PRJ Distribution Ltd. | Wholesale & retail | 2014 |
| Prodigy Renovations Ltd | Manufacturing | 2024 |
| Progression Live Limited | Education | 2019 |
| Project Pause Ltd | Information & communication | 2025 |
| Propingtons Limited | Information & communication | 2018 |
| Props Billy Limited | Administrative & support | 2019 |
| PSH Audio Limited | Arts & recreation | 2022 |
| Psychology and Therapy Services Limited | Health & social care | 2024 |
| PTL Control Ltd | Professional & scientific | 2019 |
| Ptmarine Ltd | Manufacturing | 2016 |
| Pure Effect Cleaning Services Ltd | Administrative & support | 2014 |