| SPC International Ltd | Berkshire |
| Spearhead Training Group Ltd | Oxfordshire |
| Special Projects | |
| Specialist Marketing Agency | |
| Specialist Valve Services Ltd | |
| Specific Componetns | Greater Manchester |
| Speckle Systems | |
| Speckled Frog | Cambridgeshire |
| Specle Ltd | |
| Specto Natural Ltd | |
| Spectra Displays Ltd | Cambridgeshire |
| Spectra Group (UK) Ltd | Herefordshire |
| Spectra Security Ltd | Greater Manchester |
| SpectralWorks | Cheshire |
| Spectrum Networks Solutions Ltd | |
| Speech Empowered Computing | Flintshire |
| Speech Graphics | |
| Speechmatics | |
| Speechmatics | |
| Speedie Consultants Ltd | Kent |
| Speedwell Software | Cambridgeshire |
| Spektrix | |
| Spey Software Ltd | |
| Sphaera Training Systems | Swansea |
| Sphere | Dorset |
| Sphere Fluidics | |
| Spica Media | |
| Spica Technologies Ltd | |
| Spica Technologies Ltd | |
| Spicy Pepper Ltd | |
| Spider Online | Glasgow |
| SpiderGroup | Bristol |
| Spiderscope Ltd | Leicestershire |
| Spidersnet | West Sussex |
| SpiderwebZ | Ards and North Down |
| SpiderWriting | Edinburgh |
| SpiderWriting SEO | Edinburgh |
| Spike Digital Ltd | |
| Spiky Hedgehog Web Design | Cheshire |
| SPIN Analytics | |
| Spin Ventures Ltd | Greater London |
| Spinbox Ltd | |
| Spindogs | Cardiff |
| Spink Telecom Consultants Ltd | |
| Spinning Clock Ltd | Nottinghamshire |
| Spinview | |
| Spiral Media Ltd | Lincolnshire |
| Spiral Sites | Wiltshire |
| SpiralHosting Ltd | Belfast |
| Spire Digital | Wiltshire |