| RB Models Limited | Wholesale & retail | 2025 |
| Rbalak Limited | Construction | 2025 |
| RC Construction London Limited | Construction | 2025 |
| RC1 Testing Solutions Limited | Information & communication | 2018 |
| RCA London Ltd | Construction | 2024 |
| RCW Alloy Wheel Refurb Limited | Wholesale & retail | 2025 |
| RD Impex Limited | Wholesale & retail | 2025 |
| RD Operations Ltd | Health & social care | 2024 |
| Rdda Property Investment Limited | Real estate | 2022 |
| RDT Property Holdings Limited | Financial services | 2018 |
| Read Academy Limited | Education | 2025 |
| Reading Scientific Services Limited | Professional & scientific | 1962 |
| Ready to Go Companies Limited | Professional & scientific | 2020 |
| READYFIX247 Ltd | Construction | 2026 |
| Real Future Horizons Limited | Construction | 2024 |
| Real Prodz Ltd | Wholesale & retail | 2025 |
| Realize-Services Limited | Administrative & support | 2023 |
| Rear Limited | Information & communication | 2018 |
| REC Expert Ltd | Administrative & support | 2019 |
| Reclaim Oral Health Ltd | Education | 2025 |
| Recruiteach Ltd | Education | 2019 |
| Rectory Court (High Wycombe) Residents Association Limited(The) | Real estate | 1983 |
| Recycle-A-Bike Uxbridge Ltd | Manufacturing | 2015 |
| Red Beard Rigging and Construction Ltd. | Administrative & support | 2019 |
| Red Brick Care Ltd | Health & social care | 2017 |
| Red DOT Art (Europe) Ltd | Wholesale & retail | 2005 |
| Red Leys (Uxbridge) Limited | Real estate | 2000 |
| Red Line Land Estates Ltd | Real estate | 2018 |
| Red Line Land Ltd | Real estate | 2018 |
| Red Line Land North Dorset Ltd | Construction | 2014 |
| Red Line Land Theale Ltd | Construction | 2017 |
| Red Quay Limited | Manufacturing | 2008 |
| Red Sea Trading Ltd | Wholesale & retail | 2018 |
| Red Step Kitchen Ltd | Hospitality | 2026 |
| Red Universe Ltd | Wholesale & retail | 2024 |
| Reddyhomestore Limited | Wholesale & retail | 2025 |
| Redfive Technologies Ltd | Information & communication | 2015 |
| Redline Risk Control Ltd | Professional & scientific | 2025 |
| Redloft Consultancy Ltd | Professional & scientific | 2021 |
| Redneval Ltd | Wholesale & retail | 2024 |
| Redsmoke Consulting Ltd | Wholesale & retail | 2011 |
| Redstone Audio Ltd | Administrative & support | 2025 |
| Redtape London Limited | Wholesale & retail | 2023 |
| Redwood Court Limited | Households | 1992 |
| Redwoods Property Developments Ltd | Real estate | 2019 |
| Redy Executive Ride Ltd | Transport & logistics | 2025 |
| Reetu’S Therapy Services Ltd | Health & social care | 2023 |
| Reform ADS Ltd | Professional & scientific | 2025 |
| Reformat-It Limited | Information & communication | 2016 |
| Regal Care (Stoke) Limited | Health & social care | 2019 |
| Regal Court Management Company Limited | Real estate | 1990 |
| Regal Phoenix Ltd | Professional & scientific | 2026 |
| Regency Court (Ruislip) Residents Association Limited | Households | 1981 |
| Regeneco Limited | Construction | 2009 |
| Regeneron UK Limited | Professional & scientific | 2007 |
| Regent House Malthouse Square Limited | Real estate | 2016 |
| Regent House Princes Risborough Management Co Limited | Real estate | 2013 |
| Regents Concierge Limited | Other services | 2022 |
| Regents House Management Company Limited | Households | 1995 |
| Regents Timber Company Limited | Wholesale & retail | 1996 |
| Regina Property Development Limited | Households | 2023 |
| Regions Limited | Real estate | 2009 |
| Regwill Care Ltd | Health & social care | 2025 |
| Rehmansalesreps Limited | Wholesale & retail | 2018 |
| Rehoboth Property Holdings Ltd | Real estate | 2026 |
| Reincarnation Ltd | Real estate | 2025 |
| Rejig Consulting Ltd | Information & communication | 2018 |
| Relabell Properties Limited | Real estate | 2001 |
| Relay Holdings (UK) Limited | Financial services | 2004 |
| Relay Technical Services Limited | Professional & scientific | 1987 |
| Relay Technical Transport Ltd. | Transport & logistics | 1977 |
| Reliant Medical Ltd | Other services | 2023 |
| REN Distributions LLP | | 2014 |
| Renaco Ltd | Construction | 2026 |
| Renae Cotton London Ltd | Manufacturing | 2022 |
| Rendezvous 2024 Ltd | Hospitality | 2024 |
| Rendit Management Ltd | Professional & scientific | 2026 |
| Renew IT Lifecycle Services Limited | Information & communication | 2025 |
| RENEW55 Ltd | Wholesale & retail | 2025 |
| Renfield Freight Limited | Transport & logistics | 2025 |
| Renira Global Ltd | Professional & scientific | 2025 |
| Reno Plastering and Building Company Ltd | Construction | 2025 |
| Renomex Limited | Construction | 2006 |
| Renova Cleaning Ltd | Other services | 2023 |
| Renova Home Ltd | Construction | 2026 |
| RENOVATE4YOU Ltd | Construction | 2023 |
| Rentals One Limited | Real estate | 2018 |
| Renzoni Ltd | Wholesale & retail | 2024 |
| Replenish Yourself Limited | Information & communication | 2026 |
| Resiblox Management Ltd | Households | 2025 |
| Residential Conversions (Holdings) Limited | Real estate | 1963 |
| Residential Conversions Limited | Real estate | 2024 |
| Residential Oral Healthcare Ltd | Health & social care | 2026 |
| Residents Management (NO.1) Limited | Real estate | 1985 |
| Resolute Consulting Services Limited | Information & communication | 2016 |
| Resource Experts Ltd | Professional & scientific | 2024 |
| Resources Direct Limited | Households | 2004 |
| Resourgenix Workflow Optix Limited | Administrative & support | 2025 |
| Resourgenix Works Limited | Administrative & support | 2025 |
| Response Safety Limited | Wholesale & retail | 2002 |