| Encode IT | |
| Encoded Ltd | West Sussex |
| encodeMK | |
| Encord | |
| End Design Network Services | Surrey |
| END2END Services Ltd | Berkshire |
| Endava | |
| Endo International plc | |
| Endole Ltd | |
| Endomagnetics Ltd | |
| Endothelium Scanning Nanotechnology Ltd | |
| ENERGY | |
| Energy Intelligence Centre Ltd | |
| Energy Storage News | |
| EnergySys | Edinburgh |
| Enforce Technology Ltd | West Midlands |
| Engage Convert | |
| Engage Interactive Ltd | West Yorkshire |
| Engage Invest Exploit | |
| Engage Web | Cheshire |
| Engaged Solutions | |
| EngageTech Ltd | |
| Engaging Tech | Greater London |
| Engine Creative Agency Ltd | Northamptonshire |
| Engine Shed | |
| EngineerBox | |
| Engineered Arts Ltd | |
| Engitix | |
| Enhanc3D Genomics Ltd | |
| Enhance | |
| Enhance Hosting Automation Ltd | |
| Enhance Media Ltd | Surrey |
| Enhanced Genomics | |
| Enhanced Operating Systems Ltd | Essex |
| ENI Marketing Ltd | Devon |
| Enigma Interactive Ltd | Tyne and Wear |
| Enigma Soft Ltd | |
| Enjoy Digital Communications Ltd | |
| Enkonix | |
| Enlinea Ltd | Glasgow |
| Enovate Design Ltd | Essex |
| EnR Consultancy Services | |
| Ensign Communications | Dorset |
| Ensign Solutions Ltd | Cambridgeshire |
| Ensilicated Technologies Ltd | |
| EnSpirit.Tech | |
| Ensygnia Ltd | |
| Entec Novare Ltd | Hertfordshire |
| Entegra Ltd | Surrey |
| Enteq Technologies plc | |