| Nippon Sanso Offshore Limited | Aberdeen | 1988 |
| Nippur OIL Ltd | Wallington | 2024 |
| NIQ Solutions Ltd | London | 2022 |
| Nitrogen Well Services Ltd | North Walsham | 2003 |
| Nitrotech Ltd | Lowestoft | 2001 |
| NJM Group Holdings Ltd | Edinburgh | 2017 |
| Njord Survey Ltd | Leamington Spa | 2023 |
| NJW Inspections Ltd | Aberdeen | 2022 |
| NK Consult Ltd | Derby | 2018 |
| Nkrc Ltd | Forfar | 2013 |
| NKY Consulting Ltd | Westhill | 2012 |
| NLE Engineering Limited | Stonehaven | 2006 |
| Nmos Ltd | London | 2018 |
| NN2 Newco Limited | London | 2019 |
| Nobel OIL E&P (UK) Limited | London | 2014 |
| Nobel OIL E&P Caspian Limited | London | 2016 |
| Nobel OIL E&P Management (UK) Limited | London | 2014 |
| Nobel OIL E&P North America (UK) Limited | London | 2014 |
| Nobel OIL E&P North Sea Limited | London | 2015 |
| Nobel Upstream Management Limited | London | 2019 |
| Noble Corporation 2022 Limited | Altrincham | 2020 |
| Noble Corporation PLC | Altrincham | 2020 |
| Noble Drilling UK Ltd | Altrincham | 2011 |
| Noble Energy (Oilex) Limited | London | 1964 |
| Noble Energy Capital Limited | London | 2009 |
| Noble GAS and Electric Ltd | Reading | 2024 |
| Noble Highlander UK Ltd | Altrincham | 2016 |
| Noble Holding Land Support Limited | Altrincham | 2016 |
| Noble Ndus Holdings UK Limited | Altrincham | 2022 |
| Noble Ndus UK Leasing Limited | Altrincham | 2022 |
| Noble Ndus UK Ltd | Altrincham | 2022 |
| Noble Offshore Drilling (UK) Ltd | Altrincham | 1992 |
| Noble-Parker Consulting Ltd | Norwich | 2026 |
| Noetic Mining Solutions Ltd | Ferndown | 2012 |
| Nomad Safety & Security Limited | Sunderland | 2023 |
| Nomadic Miner Ltd | Ramsgate | 2021 |
| Nomis Offshore Limited | Aberdeen | 1990 |
| Nonex Systems Limited | Market Rasen | 2012 |
| Noralis Ltd | Gloucester | 2011 |
| Nordwell Marketing Trading Ltd | London | 2025 |
| Norfolk Gravel Limited | Norwich | 1943 |
| Norm Bailie Geological Services Ltd | Belfast | 2023 |
| Norm Support Services Ltd | Aberdeen | 2022 |
| Norman Emerson Group Limited | Antrim | 1970 |
| Norman Holdings (West Wales) Limited | Cardigan | 2021 |
| Norrie Consultants Ltd | Montrose | 2019 |
| Norscot Limited | Norwich | 2001 |
| Norse Drill Ltd | London | 2026 |
| Norse Heidenong Chemical Co., Ltd | Cambridge | 2026 |
| Norse Miliff International Crop Nutrition Co., Ltd | Stafford | 2024 |
| Norse Stone Ltd. | Thurso | 2015 |
| Norse Trueman Agrochemical Co., Ltd | London | 2025 |
| North Atlantic Minerals Limited | Kilmacolm | 2012 |
| North Beds Limited | Bedford | 2012 |
| North Caspian Services Limited | London | 2004 |
| North East GAS and OIL Services Limited | Bedlington | 2020 |
| North East Trading Limited | Dundee | 2018 |
| North Falkland Exploration Company Limited | Penrith | 2018 |
| North Lincs Sand & Gravel Ltd | Doncaster | 2020 |
| North Mara Holdings (UK) Limited | London | 2022 |
| North Midland Plant Ltd | Mansfield | 2016 |
| North Offshore Services Ltd | Bridlington | 2024 |
| North Ridge Exploration Ltd | Belfast | 2014 |
| North Sea (Golden Eagle) Resources Ltd. | London | 2021 |
| North Sea Natural Resources Ltd | Dorking | 2010 |
| North Sea Production Company Limited | Liverpool | 1995 |
| North Sector Limited | Borehamwood | 2014 |
| North South Land Limited | Chipping Norton | 2025 |
| North Star Mining Limited | London | 2026 |
| North Third Engineering Ltd | Callander | 2016 |
| North Tyne Roadstone Limited | Birmingham | 1966 |
| North Wales Materials Limited | Coventry | 2018 |
| North West Aggregates (Isle of Lewis) Limited | Isle Of Lewis | 2007 |
| North West Inspections Ltd | Burnley | 2017 |
| North West Materials Limited | Coventry | 2025 |
| Northam Exploration & Consulting Ltd | Bath | 2011 |
| Northeast TYT Bolts Ltd | Ashington | 2026 |
| Northern Aierlan Flower Diamond Plant Nutrition Limited | West Midlands, England | 2025 |
| Northern Atlantic Energy Limited | Sale | 2026 |
| Northern Autofarm Ltd-The | Belfast | 2002 |
| Northern Contract Crushing Ltd | Strabane | 2022 |
| Northern Frontier Design Ltd | Alloa | 2014 |
| Northern GAS Processing Limited | London | 1993 |
| Northern Offshore U.K. Ltd | London | 2008 |
| Northern Peat and Moss Limited | Glasgow | 2014 |
| Northern Petroleum (UK) Limited | London | 2000 |
| Northern Quarries (Mountfield) Ltd | Strabane | 2021 |
| Northern Rigging Systems Ltd | Stockton-On-Tees | 2023 |
| Northern Strip Mining Limited | Chesterfield | 1981 |
| Northern Welsh Quarries Ltd | Porthmadog | 2014 |
| Northline Operations Ltd | Dundee | 2026 |
| Northshore Storage Limited | Guisborough | 2013 |
| Northstone Materials Limited | Belfast | 1941 |
| Northstone Products Limited | Litlington | 1996 |
| Northumberland Stone Limited | Bishop Auckland | 1998 |
| Norway (Amas) Agricultural Technology Co., Ltd | Beckenham | 2024 |
| Norway Aimei Green Ecological Fertilizer Co., Ltd. | Beckenham | 2025 |
| Norway Aite Farmer Group Co., Ltd | West Midlands | 2023 |
| Norway Bergen International Co., Ltd | Cardiff | 2026 |
| Norway Bonmeisen Special Agrochemical Group Co., Ltd | Beckenham | 2024 |