| H.Fine & SON Limited | Manufacturing | 1948 |
| H.H Khan of Kalat Group Limited | Administrative & support | 2024 |
| H.H.Abbs & Co Limited | Wholesale & retail | 1964 |
| H.O.T China Limited | Hospitality | 2016 |
| H.S Foods Ltd | Wholesale & retail | 2012 |
| HA Industries Ltd | Wholesale & retail | 2023 |
| HA Property Power Ltd | Real estate | 2024 |
| Haana Tech Ltd | Wholesale & retail | 2024 |
| Habitat Shutters Limited | Construction | 2013 |
| Haca Holdings Co Ltd | Financial services | 2026 |
| Hafiz & Associates Ltd | Administrative & support | 2015 |
| Haizel Williams Recruitment Ltd | Administrative & support | 2025 |
| Hajar Asset Management Limited | Real estate | 2017 |
| Hajoras Ltd | Information & communication | 2018 |
| Hakinest Construction Ltd | Construction | 2022 |
| Halal Auto Finance Limited | Wholesale & retail | 2026 |
| Halcledix Limited | Real estate | 2017 |
| Halcyon Gardens by Gerrard Limited | Administrative & support | 1996 |
| Hale Hamilton (Valves) Limited | Manufacturing | 1981 |
| Haliaeetus Ltd | Professional & scientific | 2014 |
| Hall Scenic Paintworks Ltd | Construction | 2022 |
| Hallmark of London Painting & Decorating Ltd | Construction | 2026 |
| Halo Film Services Ltd | Professional & scientific | 2025 |
| Halo Play Cafe Ltd | Hospitality | 2020 |
| Halton Road Management Company Limited | Real estate | 2008 |
| HAM Baker Engineering Limited | Manufacturing | 2022 |
| Hamara Style UK Ltd | Wholesale & retail | 2020 |
| Hambleton Close Management Limited | Households | 2015 |
| Hambridge Lane Limited | Real estate | 2023 |
| Hamden Ltd | Administrative & support | 2021 |
| Hamer International Limited | Wholesale & retail | 1990 |
| Hamid Turab Ltd | Wholesale & retail | 2025 |
| Hamilton Painting and Decorating Ltd | Construction | 2024 |
| Hamim Trading Ltd | Professional & scientific | 2022 |
| Hammalani Limited | Hospitality | 2017 |
| Hammond Road Ltd | Real estate | 2024 |
| Hamot London Limited | Manufacturing | 2026 |
| Hampden Gardens Ltd | Wholesale & retail | 2025 |
| Hampshire Barnes Ltd | Administrative & support | 2010 |
| Hampstead Electrical Ltd | Administrative & support | 2021 |
| Hampstead GAS Services Ltd | Construction | 2012 |
| Hampstead Group Ltd | Real estate | 2019 |
| Hamray Limited | Wholesale & retail | 2025 |
| Hamroldn Ltd | Real estate | 2026 |
| Hamrymco Limited | Real estate | 2017 |
| Hamzas Investments Ltd | Real estate | 2026 |
| HAN Group Investments Limited | Health & social care | 2021 |
| HAN Group Limited | Financial services | 2020 |
| HAN Property Limited | Real estate | 2022 |
| Handyfiki Limited | Transport & logistics | 2016 |
| Hanworth Freehold Ltd | Real estate | 2025 |
| Happy Friar Limited | Wholesale & retail | 2010 |
| Happy Kiddo Ltd | Manufacturing | 2023 |
| Happy Link Services Limited | Health & social care | 2015 |
| Happy Tacos Ltd | Hospitality | 2025 |
| Hapworth Properties Limited | Real estate | 2009 |
| HAQ Enterprise Motors Ltd | Wholesale & retail | 2025 |
| Harappans Construction Ltd | Construction | 2018 |
| Harbour Cars Ltd | Wholesale & retail | 2024 |
| Hardwicke Place Management Company Limited | Households | 2010 |
| Hare RAM Krishna Ltd | Health & social care | 2025 |
| Harefield Barbers Limited | Other services | 2025 |
| Harefield Food & Wine Limited | Wholesale & retail | 2013 |
| Harefield Properties Limited | Other services | 2002 |
| Harefield United Football Club Limited | Other services | 2021 |
| Harefield Windows & Doors Limited | Construction | 2017 |
| Harefield Wine Ltd | Wholesale & retail | 2022 |
| Harewoods Define Spaces Ltd | Wholesale & retail | 2015 |
| Harewoods Home Ltd | Construction | 2021 |
| Hargun Services Ltd | Construction | 2022 |
| Harishen Empire Ltd | Administrative & support | 2024 |
| Harishen Fine Arts Studio Ltd | Arts & recreation | 2024 |
| Harivox UK Limited | Wholesale & retail | 2018 |
| Harjas UK Limited | Hospitality | 2025 |
| Harjeet One Limited | Construction | 2024 |
| Harlington Group Limited | Wholesale & retail | 2018 |
| Harneet Singh Ltd | Construction | 2025 |
| Harrington Safety Ltd | Education | 2015 |
| Harrow the Hub (Holdings) Limited | Financial services | 2014 |
| Harrow the Hub Investments Limited | Real estate | 2012 |
| Harshil Captures Ltd | Professional & scientific | 2025 |
| Hart Grove Home LLP | | 2025 |
| Harte Hanks Tranquility Limited | Other services | 2016 |
| Harte Hanks UK Limited | Administrative & support | 1989 |
| Hartford Property Group Limited | Real estate | 2025 |
| Hartnett Contracting Ltd | Administrative & support | 2025 |
| Harveer Properties Ltd | Real estate | 2021 |
| Harvinder Wilkhu Consulting Ltd | Professional & scientific | 2021 |
| Hasbro Consumer Products Licensing Limited | Administrative & support | 2020 |
| Hasbro Overseas Holdings Limited | Financial services | 2013 |
| Hasbro U.K. Limited | Transport & logistics | 1986 |
| Hashi Limited | Health & social care | 2023 |
| Hasmat Safety Solutions Limited | Professional & scientific | 2011 |
| Hatara Limited | Real estate | 2023 |
| Hatch&Roost Limited | Hospitality | 2026 |
| Hatton Garden Studios Ltd | Professional & scientific | 2023 |
| Hava Homes Ltd | Real estate | 2019 |
| Haven Grove Care Ltd | Health & social care | 2026 |
| Hawkesworth Builders Limited | Construction | 2014 |
| Hawkins Accounting and Consulting Limited | Wholesale & retail | 2014 |