| HLP Sourcing Solutions Ltd | Wholesale & retail | 2024 |
| Hobbiton Holdings Limited | Real estate | 2025 |
| Hobbspass Ltd | Administrative & support | 2016 |
| Holdfast Estate Ltd | Agriculture & fishing | 2026 |
| Holistic Hounds Limited | Extraterritorial | 2020 |
| Holkham Holdings Limited | Real estate | 2025 |
| Hollywood Nail Treatments Limited | Other services | 2011 |
| Home Documentary Film Ltd | Information & communication | 2025 |
| Home of Bread Bakery Ltd | Manufacturing | 2023 |
| Home Suite Home Apartments Limited | Administrative & support | 2021 |
| Home View Landscapes Ltd | Administrative & support | 2019 |
| Home View Property Solutions Ltd | Real estate | 2025 |
| Home-Start Bracknell Forest | Health & social care | 2015 |
| Homeobject Limited | Construction | 2022 |
| Homer Interiors Limited | Construction | 2009 |
| Homesoul Limited | Wholesale & retail | 2012 |
| Honeycomb Events Ltd | Hospitality | 2025 |
| Honeywell Acquisitions II Limited | Financial services | 2006 |
| Honeywell Acquisitions Limited | Financial services | 2004 |
| Honeywell Aerospace UK Co Limited | Administrative & support | 2025 |
| Honeywell Analytics Limited | Wholesale & retail | 1946 |
| Honeywell Avionics Systems Limited | Other services | 1987 |
| Honeywell Bryan Donkin GAS Technologies Ltd. | Manufacturing | 1995 |
| Honeywell CIF Trustee Limited | Extraterritorial | 2007 |
| Honeywell Control Systems Limited | Administrative & support | 1926 |
| Honeywell Group Holding UK | Financial services | 1999 |
| Honeywell Group Holding UK II | Financial services | 1999 |
| Honeywell Group Ltd | Financial services | 1997 |
| Honeywell Holdings Limited | Financial services | 1998 |
| Honeywell International UK Limited | Financial services | 1903 |
| Honeywell Joint Ventures Limited | Financial services | 1989 |
| Honeywell Limited | Financial services | 1936 |
| Honeywell Normalair-Garrett (Holdings) Limited | Administrative & support | 1946 |
| Honeywell Normalair-Garrett Limited | Professional & scientific | 1967 |
| Honeywell North Atlantic Holdings Limited | Financial services | 2006 |
| Honeywell Pension Trustees Limited | Other services | 1958 |
| Honeywell Productivity Solutions Limited | Other services | 1995 |
| Honeywell Safety Products International Ltd. | Financial services | 2013 |
| Honeywell Touchstone Limited | Financial services | 2025 |
| Honeywell UK Limited | Manufacturing | 1935 |
| Honeywell UK Pension Scheme Trustee Limited | Other services | 2010 |
| Honeywell Ventures 2 Limited | Professional & scientific | 2000 |
| Honeywell Ventures Limited | Financial services | 1993 |
| Hortus Land & Build Ltd | Construction | 2024 |
| Hot Dogs Dog Grooming Limited | Other services | 2022 |
| Hot Food Trading Ltd | Hospitality | 2025 |
| House of Rooh Ltd | Wholesale & retail | 2025 |
| Howard Electrical and Security Services Limited | Manufacturing | 2014 |
| Howard's Property Care Limited | Administrative & support | 1990 |
| Howl's Places Ltd | Administrative & support | 2019 |
| Howley Properties Limited | Construction | 2007 |
| HR Knowledge Hub Limited | Professional & scientific | 2025 |
| HRG Consulting Ltd | Professional & scientific | 2022 |
| HRM Gifts Ltd | Wholesale & retail | 2021 |
| HSH Cleaning Group Limited | Administrative & support | 2026 |
| Hsmrs Ltd | Administrative & support | 2025 |
| Hudson Global Trading Ltd | Wholesale & retail | 2025 |
| Hughes Consultancy Service Limited | Administrative & support | 2024 |
| Hughes Estates Ltd | Real estate | 2012 |
| Hughes Group Limited | Construction | 2003 |
| Humphris Go Ltd | Transport & logistics | 2026 |
| Hunt S P Limited | Wholesale & retail | 2018 |
| Hurley Entertainment Ltd | Administrative & support | 2020 |
| Huskyy Limited | Transport & logistics | 2020 |
| Hutchreadyfood Ltd | Hospitality | 2025 |
| Hutton Premises Solutions Limited | Construction | 2002 |
| HW Nifty Gifts Ltd | Wholesale & retail | 2026 |
| Hwflowers&Foliage Ltd | Wholesale & retail | 2026 |
| Hydro Systems Europe Ltd | Administrative & support | 1996 |
| Hyra Group Ltd | Financial services | 2025 |
| I C L Pension Trust Limited | Financial services | 1951 |
| I P Henderson Holdings Limited | Construction | 2022 |
| I Pour Ltd | Manufacturing | 2016 |
| I Wentures Ltd | Transport & logistics | 2015 |
| I-4 Talent 1896 Ltd | Education | 2019 |
| I-4 Talent 1910 Ltd | Education | 2019 |
| I-4 Talent Academy Ltd | Arts & recreation | 2017 |
| I-4 Talent Athlete Management Limited | Education | 2019 |
| I.S.E & Medeiros Ltd | Real estate | 2024 |
| I7 Services Limited | Professional & scientific | 2026 |
| IBS and GUT Solutions Limited | Health & social care | 2018 |
| IBS Software Europe Limited | Information & communication | 2002 |
| Icecold Technology UK Ltd | Administrative & support | 2017 |
| Ichoice Health 2 Limited | Financial services | 2018 |
| Ichoice Health 3 Limited | Financial services | 2018 |
| Ichoice Health Limited | Financial services | 2018 |
| Icleaning & Ironing Ltd | Administrative & support | 2021 |
| Ict-Techconsulting Ltd | Information & communication | 2012 |
| ICX Applications Ltd | Information & communication | 2022 |
| ICX Limited | Information & communication | 2010 |
| Ideal Painting Limited | Construction | 2019 |
| Ideal Stays UK Ltd | Real estate | 2025 |
| Idiveteam Ltd | Arts & recreation | 2013 |
| IDM Property Enterprises Ltd | Real estate | 2018 |
| IDS Tech Solutions Ltd | Information & communication | 2026 |
| Idweb Limited | Wholesale & retail | 2000 |
| Ignition Tennis (West) Limited | Education | 2017 |
| Ignition Tennis Limited | Education | 2013 |
| Ignition Tennis Schools Limited | Education | 2017 |
| IGO Transport Limited | Transport & logistics | 2018 |