| Hounslow Pizza & Chicken Ltd | Wholesale & retail | 2024 |
| Hounslow Tops Pizza Ltd | Hospitality | 2025 |
| House Line Building Services Limited | Construction | 1994 |
| House of Cambridge Limited | Wholesale & retail | 2024 |
| House of Camden Gift Ltd | Wholesale & retail | 2025 |
| House of Chloe Outreach | Administrative & support | 2022 |
| House of Elysian Ltd | Professional & scientific | 2020 |
| House of Leather Camden Ltd | Wholesale & retail | 2023 |
| House of Lily Ltd | Education | 2025 |
| House of Pods Ltd | Wholesale & retail | 2024 |
| House of Vera Ltd | Wholesale & retail | 2024 |
| House to Home Construction Limited | Construction | 2012 |
| Housing First Group Holdings Limited | Real estate | 2026 |
| Housing First Group Limited | Real estate | 2024 |
| Hova HR Consulting Limited | Administrative & support | 2019 |
| Hoviz Limited | Professional & scientific | 2019 |
| Hoxa Ltd | Construction | 2006 |
| HQ Pro Painters Limited | Construction | 2019 |
| HQ Ultrasound Services Limited | Health & social care | 2019 |
| HRC Assets Management Ltd | Financial services | 2022 |
| HRC Pizza Group Ltd | Professional & scientific | 2020 |
| Hromei Brickwork Constructions Ltd | Construction | 2021 |
| Hrysanthemum Ltd | Administrative & support | 2022 |
| HS Auto Garage Ltd | Wholesale & retail | 2026 |
| HSE Ltd | Professional & scientific | 2025 |
| HSG Lettings Limited | Real estate | 2019 |
| HSG Soft Ltd | Information & communication | 2015 |
| HSM Engineers Limited | Professional & scientific | 2018 |
| HSO Limited | Health & social care | 2022 |
| HTG Services Ltd. | Construction | 2020 |
| HU Joy Limited | Administrative & support | 2025 |
| Hudson Antiques Limited | Wholesale & retail | 2018 |
| Hughes Portland Ltd | Professional & scientific | 2009 |
| Hugo Accounting Services Ltd | Professional & scientific | 2020 |
| Huldax Limited | Administrative & support | 2010 |
| Hull Favorite Fried Chicken Ltd | Hospitality | 2022 |
| Humbug Productions Limited | Information & communication | 2017 |
| Hummingbird Floors Limited | Construction | 2015 |
| Hunger Dome Ltd | Hospitality | 2024 |
| Hungry BUG Limited | Information & communication | 2025 |
| Hungry Stars Ltd | Professional & scientific | 2022 |
| Hunniepot Ltd | Information & communication | 2025 |
| Hunt & Antler Limited | Wholesale & retail | 2019 |
| Hunter & Hunter (Designs) Limited | Construction | 2018 |
| Hunter & Hunter (UK) Limited | Real estate | 2011 |
| Hursley Grove Property Management Company Limited | Households | 2021 |
| Hussein Studio Ltd | Professional & scientific | 2023 |
| Hutchinson Greenscapes Limited | Administrative & support | 2025 |
| Hvbhudia Ltd | Professional & scientific | 2026 |
| Hvcklife Ltd | Professional & scientific | 2025 |
| HVD Ground Work Ltd | Construction | 2020 |
| HY Microgreens Limited | Agriculture & fishing | 2025 |
| Hyde London Housing Limited | Households | 2022 |
| Hyde Park Aparts Limited | Real estate | 2019 |
| Hydean Dental Surgery Ltd | Health & social care | 2022 |
| Hydrmate Ltd | Manufacturing | 2026 |
| Hydro Limited | Construction | 2005 |
| Hydrosphere-Plumbing Ltd | Construction | 2009 |
| Hyline Energy UK Limited | Mining & quarrying | 2023 |
| Hynde Dent Limited | Health & social care | 2010 |
| Hypermatrix Solutions Limited | Information & communication | 2007 |
| Hyta Consulting Ltd | Professional & scientific | 2016 |
| I & S Rail Services Limited | Construction | 2016 |
| I AM an Overcomer Ltd | Manufacturing | 2025 |
| I Burnar Ltd | Construction | 2014 |
| I Buy London Ltd | Wholesale & retail | 2022 |
| I Cars Care Ltd | Administrative & support | 2024 |
| I CUT Salon Ltd | Other services | 2025 |
| I NAZ UK Limited | Wholesale & retail | 2020 |
| I Prestige Limited | Professional & scientific | 2015 |
| I Rock Web Ltd | Information & communication | 2025 |
| I S Design Services Limited | Professional & scientific | 2024 |
| I TIK Mobile Limited | Wholesale & retail | 2021 |
| I V Distributions Ltd | Transport & logistics | 2018 |
| I&D London Building Services Limited | Construction | 2015 |
| I-Foxmasters Ltd | Construction | 2023 |
| I-Qed Ltd | Health & social care | 2011 |
| I-Qed Properties Ltd | Real estate | 2020 |
| I.T.A PAY Solutions Ltd | Administrative & support | 2025 |
| I.T.A Tax Accounting Ltd | Professional & scientific | 2023 |
| IA Construction Ltd | Construction | 2024 |
| Iacob Rail Ltd | Construction | 2023 |
| Iadac Construct Ltd | Construction | 2019 |
| IAS Accountants Limited | Professional & scientific | 2009 |
| IB Construct Limited | Construction | 2018 |
| IB Property Management Ltd | Financial services | 2026 |
| Ibaad Khan Ltd | Wholesale & retail | 2025 |
| Ibadds Ltd | Wholesale & retail | 2010 |
| Ibase Mobile Technology Ltd | Wholesale & retail | 2026 |
| IBB Cars Limited | Wholesale & retail | 2024 |
| Ibctec Ltd | Information & communication | 2014 |
| Iberia Cars 24 Ltd | Transport & logistics | 2016 |
| Iberia Cars 24 Wolverhampton Ltd | Transport & logistics | 2026 |
| IBL London Limited | Wholesale & retail | 2023 |
| Ibrahim Enayat Ltd | Wholesale & retail | 2025 |
| Ibrahim Estate&Catering Ltd | Hospitality | 2021 |
| IBS Assets Limited | Professional & scientific | 2014 |
| IBS Technology Limited | Information & communication | 2008 |
| ICA Engineering Consultants Ltd | Professional & scientific | 2022 |
| ICA Property Services Ltd | Construction | 2024 |