| Red Eagle Finance Limited | Financial services | 2005 |
| Red Eagle Securities Limited | Construction | 2004 |
| Red Event Production Limited | Other services | 2008 |
| Red Event Production SET & Stage Limited | Professional & scientific | 2022 |
| Red FOX Innovation Ltd | Professional & scientific | 2024 |
| Red Group Limited | Construction | 2026 |
| Red House Design and Print Limited | Information & communication | 1989 |
| Red Jacket Properties Ltd | Real estate | 2025 |
| Red Kite Golf (Clapham) Limited | Hospitality | 2023 |
| Red Level Mortgages Ltd | Financial services | 2018 |
| Red Lion Horseheath Ltd | Hospitality | 2018 |
| Red Lodge Inks Limited | Wholesale & retail | 2024 |
| Red Peacock Photography Ltd | Arts & recreation | 2023 |
| Red Shark Group Limited | Information & communication | 2018 |
| Red Star Distribution (UK) Limited | Transport & logistics | 2008 |
| Red Star Investments Ltd | Real estate | 2023 |
| Red Star Property Services Ltd | Construction | 2018 |
| Red Stilettos Accountants Ltd | Professional & scientific | 2013 |
| Red Tomatoes Ltd | Information & communication | 2020 |
| Redborne Upper School and Community College | Education | 2011 |
| Redbourn Cleaning Services Limited | Administrative & support | 1999 |
| Redcoda Limited | Information & communication | 2010 |
| Redcrest Developments Limited | Construction | 2010 |
| Reddev Limited | Real estate | 2019 |
| Reddil Developments Limited | Real estate | 2010 |
| Reddil Properties Limited | Real estate | 2009 |
| Redefine MSP Ltd | Professional & scientific | 2025 |
| Redglaze Limited | Manufacturing | 2002 |
| REDHAT26 Ltd | Health & social care | 2022 |
| Redimo Hiring Solutions Limited | Administrative & support | 2026 |
| Redranch Ltd | Construction | 2025 |
| Reds Management Ltd | Administrative & support | 2017 |
| Redsky 21 Ltd | Administrative & support | 2021 |
| Redstone Publications Limited | Information & communication | 2022 |
| Redtop Repairs Ltd | Construction | 2025 |
| Reece Smith Ltd | Information & communication | 2023 |
| Reeda Safety Limited | Construction | 2011 |
| Reef Jewelry Ltd | Wholesale & retail | 2010 |
| Reef Plumbing and Maintenance Ltd | Construction | 2024 |
| Reeks Logistics Ltd | Transport & logistics | 2025 |
| Reelcode Media Ltd | Information & communication | 2024 |
| Reena's Beauty Ltd | Other services | 2023 |
| Reenie's Ice Cream Bar Ltd | Administrative & support | 2020 |
| Reevrs Ltd | Information & communication | 2023 |
| Reffs Limited | Health & social care | 2022 |
| Refined Garages Limited | Professional & scientific | 2024 |
| Refined House Studio Limited | Professional & scientific | 2026 |
| Refined Properties Limited | Real estate | 2017 |
| Reflect & Release Ltd | Health & social care | 2024 |
| Reflect Cleaning Limited | Administrative & support | 2014 |
| Reflect Design Limited | Administrative & support | 2016 |
| Reflective Care Solutions Ltd | Professional & scientific | 2023 |
| Reflective Paintwork Ltd | Wholesale & retail | 2025 |
| Regal Edge Limited | Real estate | 2025 |
| Regalcrown Limited | Extraterritorial | 2011 |
| Regalia LDN Limited | Wholesale & retail | 2024 |
| Regalswift Property Management Limited | Households | 1996 |
| Regen Property Investments Ltd | Real estate | 2019 |
| Regency Lodge Management Limited | Households | 1984 |
| Regency Logistics Ltd | Transport & logistics | 2026 |
| Regent Gate Mortgages Limited | Financial services | 2025 |
| Regent Penthouses Limited | Real estate | 2010 |
| Regent Street Estate Management Limited | Households | 2003 |
| Reggae Library Limited | Information & communication | 2025 |
| Reggae Matters Ltd | Hospitality | 2021 |
| Regimental Models and Games Ltd | Wholesale & retail | 2026 |
| Reglor Limited | Financial services | 2019 |
| Regmi Properties Ltd | Real estate | 2025 |
| Regulatory Affairs Services Ltd | Public administration | 2020 |
| Rehearsal Rooms Theatre Ltd | Education | 2024 |
| Rehoboath House Ltd | Health & social care | 2025 |
| Rehoboth Supported Services Ltd | Administrative & support | 2023 |
| Reif Construction Services Ltd | Construction | 2023 |
| Reimagined Properties Ltd | Real estate | 2024 |
| Reimer IT Consulting Ltd | Information & communication | 2024 |
| Rejuvena Skin Aesthetics Limited | Other services | 2022 |
| Rejuvenate & Radiate Ltd | Health & social care | 2024 |
| Relaxrentals Ltd | Hospitality | 2023 |
| Relayx Logistics Ltd | Transport & logistics | 2026 |
| Reliable Network Services Ltd | Information & communication | 2025 |
| Reliable Projects Ltd | Construction | 2026 |
| Reliance Care Agency Limited | Administrative & support | 2010 |
| Relic Distribution London Ltd | Transport & logistics | 2018 |
| Relmfield Court Limited | Households | 1985 |
| Relocation Haven Ltd | Hospitality | 2024 |
| Remedy & YOU Limited | Public administration | 2020 |
| Remedy Collective CIC | Arts & recreation | 2026 |
| Remity Cctv Security Ltd | Other services | 2019 |
| Remk Limited | Financial services | 2024 |
| Remma Accountancy & Tax Services Ltd | Other services | 2025 |
| Remodelar Ltd | Professional & scientific | 2025 |
| Remote Control Management Ltd | Information & communication | 2017 |
| Remus Sport Limited | Professional & scientific | 2009 |
| Remuss 1995 Services Limited | Transport & logistics | 2015 |
| Renais Investments Limited | Real estate | 1999 |
| Renaissance Gold Ltd | Other services | 2023 |
| Renard Productions | Arts & recreation | 2010 |
| Rene Plumbing & Heating Limited | Construction | 2012 |
| Renevatio Limited | Other services | 2007 |
| Renewable Energy Homes Ltd | Real estate | 2026 |