| Sparkle & Go Cleaning Company Ltd | Administrative & support | 2025 |
| Sparkle Nest Cleaning Solutions Limited | Administrative & support | 2026 |
| SPARKLE101 Cleaning Services Ltd | Administrative & support | 2021 |
| Sparkport International Limited | Wholesale & retail | 2025 |
| Sparksys Consulting Limited | Information & communication | 2014 |
| Sparktech Enterprises Limited | Information & communication | 2020 |
| Sparrows Herne Development Limited | Professional & scientific | 1955 |
| Sparsanctuary Limited | Manufacturing | 2016 |
| Spartacus Gladiators Limited | Real estate | 2024 |
| Spartan Electrical Contractors Limited | Construction | 2006 |
| Spartan Protection Ltd | Administrative & support | 2018 |
| Spartysparkles Ltd | Health & social care | 2019 |
| Spear IT Consultants Ltd | Information & communication | 2022 |
| Spear Security Ltd | Administrative & support | 2010 |
| Spears Properties Ltd | Real estate | 2019 |
| Special Bathrooms Ltd | Construction | 2025 |
| Special OPS HQ Ltd | Arts & recreation | 2013 |
| Special Seasons Ltd | Wholesale & retail | 2022 |
| Special Solutions Hub Ltd | Wholesale & retail | 2024 |
| Specialist Compliant Coatings Ltd | Manufacturing | 2001 |
| Specialist Locum Network Limited | Administrative & support | 2013 |
| Specialist Medicine Recruitment Ltd | Administrative & support | 2020 |
| Speckstein Kunst Ltd | Construction | 2010 |
| Spectacle Music Limited | Information & communication | 2013 |
| Spectr Infotech Ltd | Administrative & support | 2022 |
| Spectr Resource Management Ltd | Administrative & support | 2023 |
| Spectre Automotive Ltd | Wholesale & retail | 2024 |
| Spectre Group Ltd | Administrative & support | 2025 |
| Spectrosimeter Ltd | Other services | 2023 |
| Spectrum Coatings Services Ltd | Construction | 2021 |
| Spectrum Composite Solutions Limited | Manufacturing | 2019 |
| Spectrum Networks Solutions Limited | Information & communication | 2000 |
| Spectrum Recycling Limited | Water & waste | 2014 |
| Spectrumpharma Japan Limited | Information & communication | 2012 |
| Specxsol Limited | Wholesale & retail | 2025 |
| Spedan Ltd | Professional & scientific | 2012 |
| Speecheasy Limited | Information & communication | 2010 |
| Speed Dragon Logistics Ltd | Transport & logistics | 2021 |
| Speed Dragon Removal Ltd | Transport & logistics | 2022 |
| Speed Fit Mobile Tyres Ltd | Wholesale & retail | 2025 |
| Speed-Drop Ltd | Transport & logistics | 2018 |
| Speedframer Limited | Wholesale & retail | 1999 |
| Speedheat U.K. Limited | Wholesale & retail | 1997 |
| Speedi Tech Ltd | Information & communication | 2015 |
| Speedlight Cars Ltd | Transport & logistics | 2025 |
| Speedline Ltd | Extraterritorial | 2013 |
| Speedlink Couriers and Caterers Limited | Transport & logistics | 2024 |
| Speedograph Richfield Limited | Manufacturing | 1992 |
| Speedplus Limited | | 1986 |
| Speedswitch Ltd | Other services | 2024 |
| Speedy Claim MK Limited | Professional & scientific | 2013 |
| Speedytruck and Recovery Ltd | Water & waste | 2022 |
| Speeed Trans Ltd | Transport & logistics | 2017 |
| Spenny's Lighting KIT Rental Ltd | Information & communication | 2025 |
| Spennys Lighting Limited | Information & communication | 2008 |
| SPF (United Kingdom) Limited | Manufacturing | 2001 |
| SPH 268 Limited | Professional & scientific | 2004 |
| SPH Kitchens & Bathrooms Ltd | Construction | 2017 |
| Sphere Business Consulting Limited | Professional & scientific | 2007 |
| Sphere MK Limited | Hospitality | 2026 |
| Sphinx Metals UK Limited | Wholesale & retail | 2022 |
| Spice Bar MK Limited | Hospitality | 2023 |
| Spice Flame Brooklands Limited | Real estate | 2023 |
| Spice HUT Deanshanger Ltd | Hospitality | 2019 |
| Spice Legacy Ltd | Hospitality | 2026 |
| Spice Village MK Ltd | Hospitality | 2024 |
| Spiceloop Ltd | Manufacturing | 2026 |
| Spiceme Ltd | Wholesale & retail | 2024 |
| Spicy Chillies Ltd | Construction | 2025 |
| Spicy Lovers Ltd | Hospitality | 2025 |
| Spicy Tandoori Limited | Hospitality | 2011 |
| Spidergoat Productions Ltd | Information & communication | 2015 |
| Spike Vector Ltd | Information & communication | 2022 |
| Spinal Injuries Association | Health & social care | 1996 |
| Spinbox Ltd | Information & communication | 2007 |
| Spintech Solutions Ltd | Information & communication | 2023 |
| Spiral Galaxy Limited | Wholesale & retail | 2021 |
| Spiral Two Limited | Professional & scientific | 2013 |
| Spire Contracting Limited | Construction | 2021 |
| Spire Solutions MK Ltd | Construction | 2025 |
| Spire View Management Company Limited | Households | 1987 |
| Spirebuild Ltd | Construction | 2012 |
| Spirit Classic Wedding Cars LLP | | 2021 |
| Spirit Life International Ltd | Other services | 2025 |
| Spirit of Mexico Limited | Wholesale & retail | 2021 |
| Spirit of the Andes Limited | Wholesale & retail | 2020 |
| Spirit of the Dance Limited | Arts & recreation | 2000 |
| Spirited Initiative Ltd | Professional & scientific | 2015 |
| Spiritual Radio Services | Information & communication | 2022 |
| Spirufarm Ltd | Other services | 2024 |
| Spitfire Travel Shefford Ltd | Administrative & support | 2010 |
| SPK Property Limited | Real estate | 2019 |
| Splash Dogs UK Ltd | Other services | 2026 |
| Splatmap Limited | Information & communication | 2023 |
| Splendid SP Limited | Construction | 2004 |
| Spondoolees Ltd | Hospitality | 2006 |
| Sponsor Licence Consultants Limited | Administrative & support | 2025 |
| Spontaneous Chartering LLP | | 2016 |
| Spoolers Solutions Ltd | Information & communication | 2014 |
| Sport 4 Good Ltd | Administrative & support | 2022 |