| Organisational Excellence (Orgxl) Ltd | Professional & scientific | 2026 |
| Organo Polymers Ltd | Manufacturing | 2026 |
| Orgate Limited | Transport & logistics | 2014 |
| Orgxl Ltd | Professional & scientific | 2026 |
| Origin Construction Limited | Construction | 2015 |
| Origin Multimedia Design Limited | Information & communication | 2010 |
| Orman Ltd | Construction | 2018 |
| Ortus Consulting Limited | Extraterritorial | 2017 |
| Orunmila Solutions Ltd | Administrative & support | 2025 |
| Oscar Eleven Ltd | Real estate | 2016 |
| Oslo Luxury Limited | Wholesale & retail | 2023 |
| Osva Solutions Ltd | Information & communication | 2021 |
| OT First Ltd | Health & social care | 2009 |
| Ottomans (Blandford) Limited | Hospitality | 2005 |
| Outbreak Creative Limited | Information & communication | 2012 |
| Outfit Masters Co Ltd | Manufacturing | 2026 |
| Outfits Masters Limited | Professional & scientific | 2025 |
| Outsource Direct Ltd | Information & communication | 2020 |
| Outsource Edge Ltd | Information & communication | 2025 |
| Outstanding Construction & Design Limited | Construction | 2009 |
| Over the Stack Solutions Ltd | Information & communication | 2024 |
| OWA Holdings Ltd | Extraterritorial | 2016 |
| Owens Contracting Services Ltd | Construction | 2024 |
| Oxlio Ltd | Wholesale & retail | 2022 |
| Ozlu Limited | Hospitality | 2016 |
| OZYUR24 Ltd | Wholesale & retail | 2025 |
| P C Food and Wine Limited | Wholesale & retail | 2014 |
| P&G 2025 Ltd | Construction | 2025 |
| P&P Property Group Ltd | Real estate | 2025 |
| P.Baran Construction Ltd | Construction | 2026 |
| P.G. Marshall & Sons Limited | Construction | 1962 |
| P.G. Marshall (Builders) Limited | Construction | 1990 |
| P2P Consultancy Services Limited | Professional & scientific | 2009 |
| Pacific Ecotex UK Limited | Wholesale & retail | 2026 |
| Padel Tree Limited | Wholesale & retail | 2023 |
| PAK Salman Ltd | Hospitality | 2021 |
| PAK UK Properties Ltd | Construction | 2019 |
| Palian Ltd | Information & communication | 2023 |
| Palmer & Co Services Ltd | Construction | 2024 |
| Palmerwebb Limited | Construction | 2024 |
| Panache Events Management Limited | Hospitality | 2016 |
| Pandada Ltd | Hospitality | 2026 |
| Pannu Autos Ltd | Wholesale & retail | 2024 |
| Panoptic Labs Limited | Information & communication | 2019 |
| Papahill Limited | Hospitality | 2018 |
| Papas Tops Pizza PO2 Limited | Hospitality | 2020 |
| Parachute Local Food Ltd | Wholesale & retail | 2019 |
| Parallel Progress Limited | Administrative & support | 2016 |
| Parentline.Ai Ltd | Information & communication | 2025 |
| Parklife Partnerships Ltd | Construction | 2026 |
| Parks Dispensing Ltd | Wholesale & retail | 2024 |
| Parks Healthcare Ltd | Health & social care | 2024 |
| Parkwood Carpentry Ltd | Manufacturing | 2020 |
| Partnership for Young Merton CIC | Financial services | 2024 |
| Pasha Mediterranean Food Limited | Hospitality | 2025 |
| Pasha Smart Tech Ltd | Wholesale & retail | 2026 |
| Patel Entertainment Limited | Information & communication | 2020 |
| Patel Property 2 Ltd | Real estate | 2018 |
| Patel Property 3 Ltd | Real estate | 2018 |
| Patel Property Ltd | Real estate | 2017 |
| Pathos Continental Foods Ltd | Wholesale & retail | 2021 |
| Patient Experience (PX) Ltd | Information & communication | 2026 |
| Patient Experience Ltd | Information & communication | 2026 |
| Patio Design & Build UK Limited | Construction | 2023 |
| Patouah Parnasse Ltd | Professional & scientific | 2022 |
| Pavbuilding Ltd | Construction | 2021 |
| Payless Group Limited | Wholesale & retail | 1996 |
| Payless Supermarkets Limited | Extraterritorial | 2008 |
| PB Fasteners Ltd | Wholesale & retail | 2026 |
| PBR Medical Services Ltd | Health & social care | 2025 |
| PBS Healthcare Ltd | Health & social care | 2025 |
| PC Demolition Limited | Construction | 2018 |
| Pcdy Consultancy Ltd | Professional & scientific | 2016 |
| Peach Avenue Toys Ltd | Wholesale & retail | 2021 |
| Peal Consultants Limited | Professional & scientific | 2013 |
| Pearl Cars Ltd | Other services | 2016 |
| Pebbles Staffing & Training Limited | Administrative & support | 2015 |
| Pehnawa Couture Ltd | Wholesale & retail | 2015 |
| Pelmex Limited | Construction | 1992 |
| Pentafive Medical Ltd | Information & communication | 2015 |
| Pentland Trading Ltd | Real estate | 2021 |
| PEP Food Limited | Hospitality | 2025 |
| Peppa Cone Music Ltd | Information & communication | 2025 |
| Peqe Engineering Services Limited | Professional & scientific | 2022 |
| Perfect Travel - the Expert Travel Adivisory Ltd | Administrative & support | 2023 |
| Peri Peri Chicken Land Ltd | Hospitality | 2020 |
| Peri Peri Chicken World Ltd | Hospitality | 2026 |
| Peri Peri Grill Tooting Ltd | Hospitality | 2018 |
| Peri Peri Inn Ltd | Hospitality | 2016 |
| Perla and BOW Limited | Wholesale & retail | 2025 |
| Perla Dental Ltd | Health & social care | 2024 |
| Perrett Construction Limited | Construction | 2021 |
| Perseus Rope Access Ltd | Administrative & support | 2024 |
| Persistent Objects Limited | Information & communication | 1998 |
| Personarc Ltd | Information & communication | 2005 |
| Pest Control Epsom Ltd | Other services | 2023 |
| Pet Social Limited | Information & communication | 2016 |
| Peter Janes LLP | | 2015 |
| Peter's Carriage Ltd | Transport & logistics | 2015 |
| Peterborough Padel Limited | Wholesale & retail | 2026 |