| GR Automotive Mobile Mechanic Limited | Wholesale & retail | 2026 |
| Grabul Management Limited | Professional & scientific | 2011 |
| Grabzilla Limited | Water & waste | 2022 |
| Granularity Limited | Information & communication | 1999 |
| Green Healthy Homes Limited | Professional & scientific | 2025 |
| Green Roof Organisation Limited | Other services | 2020 |
| Greenbelt Plumbing Ltd | Construction | 2011 |
| Greenling Associates Ltd | Professional & scientific | 2016 |
| Greentech Compliance Ltd | Professional & scientific | 2025 |
| Grill Thrill Limited | Hospitality | 2025 |
| Grip UK Services Ltd | Construction | 2017 |
| GSG Consultant Services Ltd | Mining & quarrying | 2015 |
| GSL Consulting Limited | Professional & scientific | 2017 |
| Guildblocks Limited | Wholesale & retail | 2025 |
| GVA GP Ltd | Information & communication | 2019 |
| Gwas Limited | Professional & scientific | 2008 |
| Gwsg Limited | Construction | 2017 |
| H20 Marine Ltd | Professional & scientific | 2009 |
| Hacienda Studios Limited | Professional & scientific | 2023 |
| Halcon Distribution Ltd | Wholesale & retail | 2021 |
| Halliford Cafe Ltd | Hospitality | 2019 |
| Halliford Consultants Ltd | Professional & scientific | 2015 |
| Halliford School Limited | Education | 1956 |
| Hamhaugh Hops Limited | Manufacturing | 2024 |
| Hammerton's Moorings Limited | Transport & logistics | 2024 |
| Handy UVC Ltd | Wholesale & retail | 2020 |
| Harmony OT Limited | Health & social care | 2025 |
| Harps Oak Lane Limited | Construction | 2024 |
| Harris Way Ltd | Other services | 2020 |
| Harst LLP | | 2026 |
| Hartom Limited | Professional & scientific | 1995 |
| Harvey UBI Ltd | Professional & scientific | 2015 |
| Hasmyidentitybeenstolen.Com Limited | Extraterritorial | 2015 |
| Hatfieldslondon Ltd | Hospitality | 2017 |
| Haywards Dog Spa & Boutique Ltd | Other services | 2026 |
| Haywoods Glazing Services Limited | Construction | 2005 |
| Head Consultants Limited | Education | 2018 |
| Heathrow Personnel Limited | Administrative & support | 2008 |
| Heia Viking Limited | Information & communication | 2024 |
| Helenian Consultancy Ltd | Administrative & support | 2016 |
| Helihubb Limited | Professional & scientific | 2024 |
| Heynes Solutions Ltd | Manufacturing | 2015 |
| Highcalibre Management Limited | Professional & scientific | 2014 |
| Hiten Makwana Ltd | Information & communication | 2015 |
| HL at Limited | Hospitality | 2020 |
| Home Renovation City Ltd | Construction | 2022 |
| Homely Ltd | Real estate | 2012 |
| Hooh Ltd | Real estate | 2023 |
| Hopkins Decorating Ltd | Construction | 2024 |
| House of Impact Ltd | Financial services | 2020 |
| House of Impact Talent Solutions Ltd | Administrative & support | 2025 |
| HR MOT Ltd | Wholesale & retail | 2025 |
| Hring Consulting Services Ltd | Professional & scientific | 2015 |
| Hsask Ltd | Real estate | 2022 |
| Hstewart Consulting Ltd | Professional & scientific | 2024 |
| I Ellwood Limited | Information & communication | 2015 |
| Iagp Limited | Professional & scientific | 2020 |
| IAN Allan (Miniature Railway Supplies) Limited | Arts & recreation | 1968 |
| IAN Allan Group Limited | Professional & scientific | 1962 |
| IAN Allan Motors Limited | Wholesale & retail | 1968 |
| IAN Allan Publishing Ltd | Wholesale & retail | 1945 |
| IAN Melhuish Electrical Services Limited | Construction | 2010 |
| Ice on the Poles Limited | Professional & scientific | 2008 |
| Iconic D Ltd | Wholesale & retail | 2025 |
| Identity Intelligence Limited | Information & communication | 2008 |
| Idkl Ltd | Professional & scientific | 2024 |
| Image Works (London) Ltd | Professional & scientific | 2003 |
| Immi Consultants Ltd | Professional & scientific | 2016 |
| Impressive Looks 4 U Limited | Other services | 2011 |
| Infortect Limited | Professional & scientific | 2017 |
| Infranet Ltd | Information & communication | 2019 |
| Ingenuity Connect Limited | Arts & recreation | 2023 |
| Ingenuity Fantasy Football Limited | Arts & recreation | 2025 |
| Ingenuity Loop Limited | Arts & recreation | 2023 |
| Inky Business Ltd | Manufacturing | 2023 |
| Innes Roofing Ltd | Construction | 2026 |
| Innovatesafe Limited | Administrative & support | 2024 |
| Innovative Networks Ltd | Construction | 2010 |
| Integra Asset Consultancy Ltd | Professional & scientific | 2016 |
| Integrated Programme Solutions Ltd | Professional & scientific | 2015 |
| Integrity GAS Solutions Limited | Construction | 2020 |
| Inter County Construction Limited | Construction | 1993 |
| Interlight Electrical Limited | Construction | 2009 |
| Intura Daylight Systems Ltd | Wholesale & retail | 2025 |
| Iqonic Ltd | Professional & scientific | 2017 |
| IR4 Limited | Professional & scientific | 2021 |
| Irha Solution Limited | Wholesale & retail | 2025 |
| Island Motors Ltd | Wholesale & retail | 2024 |
| Italian Pizza Experts Ltd | Hospitality | 2017 |
| J & a Recovery & Rescue Ltd | Transport & logistics | 2014 |
| J H Specialist Property Services Ltd | Real estate | 2025 |
| J H Specialist Roofing Ltd | Construction | 2011 |
| J Taylor Designs Limited | Professional & scientific | 2026 |
| J.Mc Electrical Limited | Construction | 2003 |
| JAI Food Distribution Ltd | Wholesale & retail | 2024 |
| James Crook Consultancy Ltd | Professional & scientific | 2015 |
| James D Health Limited | Information & communication | 2021 |
| Jarevolutions Ltd | Wholesale & retail | 2025 |
| Jayfern Limited | Professional & scientific | 1991 |
| JB VFX Ltd | Other services | 2010 |