| Pheb's Childminding Ltd | Health & social care | 2023 |
| Phil Dunlop Studio Ltd | Other services | 2018 |
| Phil Ratcliffe Limited | Professional & scientific | 2025 |
| Phil Watson Civil Engineering Limited | Administrative & support | 2000 |
| Philcaro Group Engineering Ltd | Professional & scientific | 2018 |
| Philios Technologies UK Limited | Information & communication | 2018 |
| Philip Dilley Consulting Limited | Professional & scientific | 2014 |
| Philippa Ferguson Consulting Ltd | Professional & scientific | 2019 |
| Phillips Living Ltd | Real estate | 2025 |
| Philliskirk Consultancy Limited | Professional & scientific | 2014 |
| Phillois Limited | Hospitality | 1999 |
| Philmor Health Care Solutions and Traders Private Limited | Health & social care | 2014 |
| Philmore Contracting Limited | Construction | 1977 |
| Phinesse Limited | Administrative & support | 2013 |
| Phipps Northampton Brewery Company Limited | Manufacturing | 2004 |
| PHM Business Services Ltd | Administrative & support | 2019 |
| PHM20 Group Holdings Ltd | Professional & scientific | 2025 |
| Phobus Presage Limited | Extraterritorial | 2012 |
| Phoenix Cleaning (MK) Ltd | Administrative & support | 2012 |
| Phoenix County Metals Limited | Water & waste | 1984 |
| Phoenix Creative Solutions Limited | Information & communication | 2012 |
| Phoenix Drinks Group Limited | Wholesale & retail | 2018 |
| Phoenix FT Consultancy Ltd | Professional & scientific | 2026 |
| Phoenix Glass Services Limited | Manufacturing | 1998 |
| Phoenix Medical Equipment Limited | Wholesale & retail | 2017 |
| Phoenix Motorcycle Training Buckinghamshire Ltd. | Professional & scientific | 2019 |
| Phoenix Organization Inc | | 1984 |
| Phoenix Patrol Limited | Administrative & support | 2024 |
| Phoenix Property Plus Ltd | Real estate | 2019 |
| Phoenix Secure Transport Ltd | Transport & logistics | 2024 |
| Phoenix Survey Services Ltd | Administrative & support | 2007 |
| Phoenix Trans Express Ltd | Construction | 2019 |
| Phoenix Turnkey Construction Ltd | Construction | 2016 |
| Phoenix VEE Company Limited | Health & social care | 2017 |
| Phoenix Vehicles Limited | Transport & logistics | 1999 |
| Phoenyx Constructions Ltd | Construction | 2014 |
| Phone Case Bakery Limited | Wholesale & retail | 2017 |
| Phone FIX Morrison Limited | Wholesale & retail | 2024 |
| Photon Holdings Limited | Construction | 2017 |
| Photongrow Lighting Ltd | Manufacturing | 2020 |
| Photongrow Ltd | Manufacturing | 2017 |
| Photonholdings Group Ltd | Construction | 2020 |
| Physically Active ( Northamptonshire) Limited | Arts & recreation | 2023 |
| Physically Active Ltd | Arts & recreation | 2015 |
| Physio Experts Clinics Limited | Health & social care | 2019 |
| Physio Shack Ltd | Health & social care | 2026 |
| Physiofirst Limited | Professional & scientific | 1996 |
| Physiofunction (Supplies) Ltd | Health & social care | 2007 |
| Physiofunction Limited | Health & social care | 2003 |
| Physiorehab Limited | Health & social care | 2020 |
| Physiotherapy Elite Limited | Health & social care | 2011 |
| PI Building Services Ltd | Construction | 2008 |
| PIA Stanchina Ltd | Professional & scientific | 2016 |
| Piango Business Club Limited | Extraterritorial | 2021 |
| PIB Welding Services Ltd | Manufacturing | 2022 |
| Pibworth Holdings Limited | Real estate | 2017 |
| Pic-Auto Ltd | Wholesale & retail | 2023 |
| Picard Solutions Limited | Information & communication | 2001 |
| Picasso Before Breakfast Limited | Professional & scientific | 2024 |
| Pichincha Limited | Professional & scientific | 2023 |
| Piciu BOJ Ltd | Transport & logistics | 2024 |
| Pick Arthey (Oundle) Limited | Wholesale & retail | 1986 |
| PICK10 Ltd | Arts & recreation | 2007 |
| Pickett Interiors and Shopfitting Limited | Extraterritorial | 2011 |
| Picture Perfect Framing & Print Ltd | Manufacturing | 2025 |
| Picture Perfect Framing Limited | Manufacturing | 2016 |
| Pidgen Properties Ltd | Real estate | 2025 |
| Pidy Ltd. | Manufacturing | 1997 |
| PIE Humble Limited | Arts & recreation | 2023 |
| Pierre Antoye Limited | Health & social care | 2010 |
| PIG Media Limited | Information & communication | 2010 |
| Pigstat Analytics Ltd | Information & communication | 2026 |
| Pikn.Id Consulting Ltd | Administrative & support | 2019 |
| Piksis Limited | Transport & logistics | 2017 |
| PIL Gritblast Limited | Professional & scientific | 2016 |
| Pilancon Services Limited | Professional & scientific | 2018 |
| Pilgrim Spirit Ltd | Manufacturing | 2017 |
| Pilgrims Rest (Kempston) Management Company Limited | Households | 2009 |
| Pilkington Communications Limited | Information & communication | 2013 |
| Pillarays (Living) Care Ltd | Health & social care | 2024 |
| Pillars of Protection Limited | Financial services | 2014 |
| Pilot Lighting Limited | Information & communication | 2016 |
| Pilotfish Trading Limited | Wholesale & retail | 2003 |
| Pilta Limited | Hospitality | 2023 |
| Pilutu Trans Limited | Transport & logistics | 2023 |
| PIN High Virtual Golf Limited | Arts & recreation | 2024 |
| PIN UP Hair & Co Northampton Limited | Other services | 2025 |
| Pinacle Workforce Solutions Ltd | Administrative & support | 2024 |
| Pinch My BUN Ltd | Hospitality | 2019 |
| Pinches Pilates Ltd | Health & social care | 2026 |
| Pinchmill Leathers Limited | Wholesale & retail | 1997 |
| Pinder Land Co. (Humberside) Limited | Construction | 1979 |
| Pindoo Limited | Wholesale & retail | 2021 |
| Pine Hills Properties Ltd | Real estate | 2025 |
| Pineapple Media Limited | Administrative & support | 2007 |
| Pineapple View Media Ltd | Professional & scientific | 2023 |
| Pinehurst Developments Limited | Construction | 2025 |
| Pineleaf Ltd | Hospitality | 2024 |
| Pines Close Management Company Ltd | Extraterritorial | 2024 |
| Pinewood Properties (Northampton) Limited | Real estate | 1993 |