| # | Company / Organisation | Region | |
|---|---|---|---|
| 1 | 3T RPD | South East | Details |
| 2 | 3M UK PLC | South East | Details |
| 3 | 3bridge consultancy | South East | Details |
| 4 | AFE technology co... | South West | Details |
| 5 | AFL telecommunica... | South West | Details |
| 6 | AGK-World Ltd | South East | Details |
| 7 | ATI, University o... | South East | Details |
| 8 | Advanced Fibreopt... | South East | Details |
| 9 | Aeroflex | Eastern | Details |
| 10 | Agilent Technologies | South East | Details |
| 11 | Alexander Capital... | Eastern | Details |
| 12 | Alpha Contract En... | South West | Details |
| 13 | Alrad Instruments... | South East | Details |
| 14 | Amazing Communica... | Eastern | Details |
| 15 | American Technica... | South East | Details |
| 16 | Ancient & Moder... | South East | Details |
| 17 | Arden photonics | Midlands | Details |
| 18 | Artemis Optical | South West | Details |
| 19 | Association of In... | South East | Details |
| 20 | Av optics | South West | Details |