| Eliemount Limited | Laurencekirk | 1997 |
| Elite Offshore Services Ltd | Rotherham | 2025 |
| ELITE82 Inspections Ltd. | Edinburgh | 2020 |
| Elizur Group Inc. Ltd | Dagenham | 2013 |
| Elka Shetland Ltd | Brae | 2024 |
| Ellash Inspection Solutions Ltd | Blackpool | 2020 |
| Elle Consultants Ltd | Montrose | 2017 |
| Ellesmere Sand & Gravel Co. Limited | Shropshire | 1959 |
| Elliott Technical Services Ltd | Pembroke | 2018 |
| Ellipsis Energy Limited | Preston | 2024 |
| Ellmas Ltd | Banff | 2014 |
| Elmside Transport Ltd | Hoddesdon | 2023 |
| Elsawi Group Limited | London | 2023 |
| Else Minerals Limited | Plymouth | 2012 |
| Elswick Energy Limited | Windsor | 2013 |
| Elswick Power Limited | London | 2013 |
| Emerald Diagold Group Ltd | Ilford | 2019 |
| Emergency Command and Control Ltd | Avoch | 2019 |
| Emerson Access Ltd | London | 2024 |
| Emerson Sand & Gravel Limited | Antrim | 2006 |
| Emiran OIL International Limited | Middlesex | 2005 |
| Emjay LNG Limited | Guildford | 2010 |
| Emmy Consultants Limited | Milltimber | 2005 |
| Emon (UK) Limited | Petersfield | 2009 |
| Emov Limited | London | 2019 |
| EMP Exploration (Kangean) Limited | London | 1966 |
| Empyrean Energy PLC | London | 2005 |
| EMR Partners Limited | Lincoln | 2023 |
| EMS OIL Limited | Stoke-On-Trent | 2011 |
| Enarji Ltd | West Byfleet | 2024 |
| Encon Solutions Ltd. | | 2007 |
| Encore OIL Limited | Birmingham | 1997 |
| Endeavour Mining PLC | London | 2021 |
| Endeavour OIL & GAS Limited | London | 1996 |
| Enegeesolutions Limited | South Ockendon | 2024 |
| Enercomp Limited | Nottingham | 2018 |
| Enerdeep Limited | Glasgow | 2010 |
| Energean Group Services Limited | London | 2018 |
| Energean UK Ltd | London | 2008 |
| Energold Drilling (Emea) Limited | Warwick | 2012 |
| Energy (PHT GP) Limited | Cardiff | 2005 |
| Energy Alloys UK Limited | Rotherham | 2004 |
| Energy Commercialisation Ltd | London | 1997 |
| Energy Delivery Solutions Ltd | London | 2022 |
| Energy Development International Limited | Aberdeen | 2026 |
| Energy Equity Resources (Norway) Limited | Kingston Upon Thames | 2004 |
| Energy Essence Ltd | London | 2011 |
| Energy Geoservices Ltd | Newbury | 2022 |
| Energy Horizons Ltd | London | 2026 |
| Energy Infrastructure Investment Company Limited | London | 2020 |
| Energy Invest Group Limited | London | 2008 |
| Energy Law Solutions Limited | Gerrards Cross | 2015 |
| Energy Levels Ltd | Reading | 2018 |
| Energy Marine Consultancy Services Limited | Lowestoft | 2021 |
| Energy Mining Advisory Partnership Ltd | Cambridge | 2020 |
| Energy PTS Ltd | Montrose | 2010 |
| Energy Rate Trading and Finance Services Limited | Enfield | 2022 |
| Energy Recovery Investments Limited | Gwent | 2008 |
| Energy Resource Limited | London | 1996 |
| Energy Resource Technology (U.K.) Limited | Aberdeen | 2004 |
| Energy Technology Limited | Stonehouse | 2024 |
| Energybuild Limited | Neath | 2003 |
| Energybuild Mining Limited | Neath | 2003 |
| Energydynamix Limited | Aberdeen | 2025 |
| Energyex Group Limited | Cupar | 2025 |
| Energypathways Irish Sea Limited | Worthing | 2021 |
| Energypathways UK Holdings Ltd. | Worthing | 2021 |
| Enerkem Limited | London | 2015 |
| Enertech Completions Limited | Aberdeen | 2026 |
| Enervative Limited | Dundee | 2007 |
| Enervision Limited | Northwood | 2021 |
| Enes North Sea Limited | Aberdeen | 2007 |
| Engen Petroleum (DRC) Limited | London | 1998 |
| Engineering Innovation & Design Limited | Aberdeen | 2003 |
| Engineering Insights Limited | Aberdeen | 1998 |
| Engineering Subsea Solutions Ltd | Ellon | 2021 |
| Engineering Supplies OIL & GAS Limited | Tiverton | 2018 |
| ENI Ambalat Limited | London | 2000 |
| ENI Arguni I Limited | London | 2011 |
| ENI Australia Limited | London | 1971 |
| ENI Bukat Limited | London | 1999 |
| ENI CBM Limited | London | 2009 |
| ENI East Ganal Limited | London | 2018 |
| ENI East Sepinggan Limited | London | 2012 |
| ENI Gambia Limited | London | 2025 |
| ENI Ganal Limited | London | 1999 |
| ENI Hewett Limited | Aberdeen | 1984 |
| ENI Hydrocarbons Venezuela Limited | London | 1979 |
| ENI in Amenas Limited | Aberdeen | 1991 |
| ENI India Limited | London | 1992 |
| ENI IS Exploration Limited | London | 1970 |
| ENI Jpda 03-13 Limited | London | 1991 |
| ENI Lasmo PLC | London | 1971 |
| ENI Liverpool Bay Operating Company Limited | London | 1971 |
| ENI LNS Limited | London | 1970 |
| ENI North Ganal Limited | London | 2011 |
| ENI OIL Algeria Limited | London | 1988 |
| ENI Peri Mahakam Limited | London | 2023 |
| ENI Rapak Limited | London | 1999 |
| ENI TNS Limited | Aberdeen | 1974 |