| Niche Place Limited | Construction | 2021 |
| Nichely Ltd | Information & communication | 2026 |
| Nicholas Vanburgh Limited | Professional & scientific | 2006 |
| Nicholas YAW Ansah Bekae Ltd | Professional & scientific | 2026 |
| Nick T Creative Limited | Professional & scientific | 2007 |
| Nicki Rutter Ltd | Professional & scientific | 2007 |
| Nicole Lane Architectural Design Studio Ltd | Professional & scientific | 2025 |
| Nigel Gambier Limited | Professional & scientific | 2011 |
| Nigerian Women in UK CIC | Other services | 2024 |
| Night Star Services Ltd | Transport & logistics | 2019 |
| Nightingale Contract Services Group Limited | Financial services | 2004 |
| Niinii Ltd | Wholesale & retail | 2025 |
| Nika Geospatial Imagery and Systems Ltd | Wholesale & retail | 2023 |
| Nikas Interior Limited | Construction | 2022 |
| Nikola 369 Ltd | Information & communication | 2025 |
| Nikzad Ltd | Real estate | 2021 |
| Nilo Property Ltd | Real estate | 2022 |
| Nimsz Property Ltd | Real estate | 2024 |
| Nine SIX Property Management Limited | Real estate | 2025 |
| NINE23 Consulting Limited | Professional & scientific | 2023 |
| Nineties Teen Theatre Productions Ltd | Administrative & support | 2021 |
| Ninetyflow Ltd | Information & communication | 2024 |
| Ningbo Mehe Industrial Co., Ltd | Extraterritorial | 2016 |
| Ninham Ltd | Information & communication | 2026 |
| Ninite UK Ltd | Information & communication | 2025 |
| Ninja Seats Ltd | Wholesale & retail | 2025 |
| Ninjashout Ltd | Information & communication | 2019 |
| Niro Accountancy Limited | Professional & scientific | 2018 |
| Niro Retail Services Limited | Wholesale & retail | 2024 |
| Nirvana Asset Limited | Financial services | 2022 |
| Nishana Ltd | Health & social care | 2021 |
| Nitrous Competitions Limited | Other services | 2018 |
| Nivaara Ltd | Health & social care | 2025 |
| Nivanpedge Ltd | Information & communication | 2022 |
| Nivax Limited | Information & communication | 2019 |
| Nivetha Limited | Extraterritorial | 2025 |
| Nixey Sound & Communications Ltd | Manufacturing | 2017 |
| NJ Specialist Limited | Wholesale & retail | 2021 |
| Njlf Holdings Fiduciary Limited | Financial services | 2025 |
| Njlf Holdings Limited | Professional & scientific | 2025 |
| NJW Lifts Ltd | Professional & scientific | 2025 |
| NK Franchising Ltd | Arts & recreation | 2026 |
| Nkdeals Limited | Wholesale & retail | 2026 |
| Nkeiru Limited | Wholesale & retail | 2005 |
| NKS Group Limited | Real estate | 2020 |
| NMH Accounting Ltd | Extraterritorial | 2023 |
| Nmkg Ltd. | Wholesale & retail | 2025 |
| Nmsbp Limited | Professional & scientific | 2026 |
| Nmthree Ltd | Wholesale & retail | 2025 |
| NNK Properties & Investments Ltd | Real estate | 2024 |
| NO Fear Cricket Coaching Ltd | Education | 2022 |
| NO Fixed Abode London Ltd | Manufacturing | 2014 |
| NO Rules Beverage Group Ltd | Manufacturing | 2025 |
| NO Rules Drinks Limited | Manufacturing | 2025 |
| NO Surface Left Ltd | Professional & scientific | 2026 |
| NO Victory Stands Alone Ltd | Wholesale & retail | 2023 |
| No'Am Organics Limited | Manufacturing | 2026 |
| Noble Art Creations Limited | Arts & recreation | 2017 |
| Noble Cleaning & Dog Walking Services Limited | Administrative & support | 2025 |
| Noble Cruncher Ltd | Information & communication | 2020 |
| Noble Nights Ltd | Hospitality | 2023 |
| Noble Software Ltd | Information & communication | 2026 |
| Noblepro Ltd | Wholesale & retail | 2018 |
| Nobletek Limited | Financial services | 2010 |
| NOC3 Protection Ltd | Extraterritorial | 2010 |
| Nocho Limited | Construction | 2023 |
| Noct Visuals Ltd | Wholesale & retail | 2024 |
| Noctua Aerial Ltd | Information & communication | 2019 |
| Nodresscode Ltd | Arts & recreation | 2025 |
| Nofre Ltd | Information & communication | 2024 |
| Noire Apparel Ltd | Manufacturing | 2025 |
| Noise Info Ltd | Professional & scientific | 2015 |
| Noissap Ltd | Real estate | 2021 |
| Nolvo&Aura Ltd | Wholesale & retail | 2025 |
| NOM NOW Ltd | Wholesale & retail | 2024 |
| Nomadic Barbers Ltd | Other services | 2023 |
| Nonstopgg Ltd | Wholesale & retail | 2024 |
| Noodlefirst Limited | Hospitality | 2024 |
| Nookedup Ltd | Wholesale & retail | 2024 |
| Noon Elite Ltd | Information & communication | 2026 |
| Noonstead Limited | Wholesale & retail | 2023 |
| Norcroft Equestrian Developments Ltd | Construction | 2019 |
| Nordic Greens Employment Ltd | Professional & scientific | 2025 |
| Nordic Loft Ltd | Wholesale & retail | 2021 |
| Nordicnest Property Limited | Real estate | 2025 |
| Norexen Consulting Limited | Professional & scientific | 2025 |
| Norfco Ltd | Wholesale & retail | 2023 |
| Norfolk & Suffolk Financial Services Limited | Financial services | 1974 |
| Norfolk Coast B&B Cottages & Camping LLP | | 2015 |
| Norfolk Computer Services IT Limited | Information & communication | 2021 |
| Norfolk Surface Coatings Limited | Professional & scientific | 2010 |
| Noribi UK Ltd | Wholesale & retail | 2026 |
| Norstone SB Limited | Real estate | 2021 |
| North Castle Properties Ltd | Real estate | 2025 |
| North Country Developments Limited | Construction | 2011 |
| North Country Holdings Limited | Financial services | 2024 |
| North Ocean Global Ltd | Information & communication | 2025 |
| North Signal Ltd | Extraterritorial | 2025 |
| North Terrace Retail Ltd | Wholesale & retail | 2023 |
| North West Property Holdings Group Limited | Real estate | 2025 |