| Red DUB Media Limited | Information & communication | 2005 |
| Red Face Consulting Ltd | Professional & scientific | 2017 |
| Red Girl Ltd | Arts & recreation | 2017 |
| Red Holdings Limited | Hospitality | 2008 |
| Red House Apartments Ltd | Real estate | 2016 |
| Red Jarr Developments Limited | Construction | 2020 |
| Red Kite Consultancy Solutions Ltd | Professional & scientific | 2016 |
| Red Kite Games Limited | Information & communication | 2012 |
| Red Kite Software Development Limited | Information & communication | 2018 |
| Red Line Designs Yorkshire Ltd | Construction | 2019 |
| Red Line Support Services Ltd | Administrative & support | 2024 |
| Red Lodge Agency Limited | Administrative & support | 2010 |
| Red Magpie Properties Limited | Real estate | 2024 |
| Red Mosquito Developments Limited | Real estate | 2022 |
| Red PEN Promotions Ltd | Arts & recreation | 2024 |
| Red Robin Productions Ltd | Arts & recreation | 2024 |
| Red Rock Inns Limited | Hospitality | 2012 |
| Red Sea Cafe 27 Ltd | Hospitality | 2026 |
| Red Sea Market Ltd | Wholesale & retail | 2015 |
| Red Sea Mini Market Limited | Wholesale & retail | 2024 |
| Red Sky Inns Limited | Hospitality | 2012 |
| Red Smoke Automotive Centre Ltd | Wholesale & retail | 2022 |
| Red Star Construction (Darnall) Ltd | Construction | 2007 |
| Red Star Entertainment Limited | Information & communication | 2009 |
| Red Star Films Limited | Information & communication | 2011 |
| Red Star Food Ltd | Wholesale & retail | 2024 |
| Red Star Immersive Limited | Administrative & support | 2015 |
| Red Star Live Limited | Information & communication | 2025 |
| Red Star Statistics Ltd | Professional & scientific | 2018 |
| Red Star Studio Limited | Information & communication | 2004 |
| Red Tapir Limited | Professional & scientific | 2025 |
| Red Thru Purple Limited | Hospitality | 2016 |
| Red Thru Purple Trading Co Limited | Hospitality | 2017 |
| Red-Eye (UK) Limited | Manufacturing | 1999 |
| Redbill Electrical Ltd | Manufacturing | 2023 |
| Redbrick Leisure Limited | Hospitality | 2018 |
| Redbrik Media Limited | Professional & scientific | 2019 |
| Redcycles CIC | Health & social care | 2025 |
| Reddy & Shorty Properties Limited | Real estate | 2014 |
| Redefine Health and Wellbeing Ltd | Health & social care | 2022 |
| Redfearn Homes Ltd | Real estate | 2026 |
| Redfern Property Development Ltd | Real estate | 2025 |
| Redgrave Consulting Ltd | Health & social care | 2026 |
| Redi Commodities Ltd | Wholesale & retail | 2025 |
| Redkat Design Ltd | Professional & scientific | 2022 |
| Redlake Developments Ltd | Construction | 2025 |
| Redlight Music Ltd | Information & communication | 2012 |
| Redline CNC Systems Limited | Manufacturing | 2013 |
| Redline Motors Shefield Ltd | Wholesale & retail | 2026 |
| Redlion Beauty & Fashion Limited | Professional & scientific | 2021 |
| Redmile Homes Limited | Extraterritorial | 2016 |
| Redmires Building Services Limited | Construction | 1975 |
| Redroad FM Limited | Arts & recreation | 2007 |
| Redstar Services Limited | Administrative & support | 2021 |
| Redstart Medical Writing Ltd | Other services | 2023 |
| Reduard Ltd | Other services | 2017 |
| Redux-Sys Ltd | Professional & scientific | 2026 |
| Redvers Investments Ltd | Real estate | 2010 |
| Redwood Industries Limited | Other services | 1995 |
| Redwood Solutions Ltd | Professional & scientific | 2025 |
| Reece Marshall Personal Training Ltd | Education | 2024 |
| Reeds Future Properties Ltd | Real estate | 2025 |
| Reegs Automation Ltd | Information & communication | 2025 |
| Reeks & Daughters Limited | Construction | 2016 |
| Reeks & Daughters Property Limited | Real estate | 2022 |
| Reelted Ltd | Real estate | 2026 |
| Reemo Ltd | Construction | 2017 |
| Reepel Ltd | Manufacturing | 2020 |
| Reeve NOT Reeves Ltd | Professional & scientific | 2023 |
| Reeve-Sims Limited | Financial services | 2001 |
| Ref-Accion Ltd | Real estate | 2023 |
| Referral Partners Limited | Professional & scientific | 2025 |
| Refill Tree Limited | Wholesale & retail | 2023 |
| Refinement Ltd | Hospitality | 2022 |
| Refix ENT Ltd | Information & communication | 2024 |
| Reflection Wardrobes Limited | Manufacturing | 2017 |
| Reflections Aesthetics Ltd | Other services | 2015 |
| Reflective Minds Limited | Health & social care | 2015 |
| Reflex Camera and Accessories Ltd | Wholesale & retail | 2024 |
| Refmatec Limited | Manufacturing | 2023 |
| Refmet Ceramics Limited | Manufacturing | 1989 |
| Reforge Change Limited | Professional & scientific | 2024 |
| Reform Road Safety & Education Limited | Education | 2004 |
| Reformer Inc Ltd | Arts & recreation | 2024 |
| Refractory Services Limited | Manufacturing | 2021 |
| Reframe Developments Limited | Professional & scientific | 2024 |
| Refresh Property Care Limited | Households | 2019 |
| Refresh Services Limited | Administrative & support | 2001 |
| Refrigerated Trailer Sales and Hire Limited | Wholesale & retail | 2014 |
| Refrigeration & Shopfitting Ltd | Other services | 2024 |
| Refs International Ltd | Financial services | 2006 |
| Refurb Laptops and Accessories Limited | Wholesale & retail | 2014 |
| REFURB365 Ltd | Construction | 2024 |
| Regal Accounting Services (Luton) Limited | Professional & scientific | 2018 |
| Regal Accounting Services Ltd | Professional & scientific | 2011 |
| Regal Blinds U.K. Limited | Wholesale & retail | 2018 |
| Regal Keys Limited | Households | 2026 |
| Regal Paints Limited | Manufacturing | 1993 |
| Regal Payroll Services Limited | Professional & scientific | 2012 |
| Regal Umbrella Services Ltd | Professional & scientific | 2017 |