| - UK | 6 |
| 25 North Colonnade - England | 1800 |
| Abbotthome - Lincolnshire | 1 |
| ABB UK Hams Hall - Warwickshire | 20 |
| Aberdeen - Aberdeen City & Shire | 3 |
| Aberdeen City Council - Aberdeen City & Shire | 8500 |
| Aberdeen Maternity Hospital - Aberdeen City & Shire | 3000 |
| Aberdeen Royal Infirmary (ARI) - Aberdeen City & Shire | 6000 |
| Aberdeenshire Council - Aberdeen City & Shire | 15000 |
| ABL (Aberdeen) - Aberdeen City & Shire | 500 |
| Aboyne Academy Staff - Aberdeen City & Shire | 93 |
| Abzena - Cambridgeshire and Peterborough | 100 |
| Acal BFI - Wokingham | 97 |
| Accrington St Christopher’s CE High School - Lancashire | 90 |
| Active Devon - UK | 26 |
| Active Lancashire - Lancashire | 45 |
| Active Lincolnshire - Lincolnshire | 12 |
| Addenbrooke's hospital - Cambridge - Cambridgeshire and Peterborough | 10000 |
| AECOM London - Aldgate Connect BID | 2000 |
| ageas - Gloucester - Gloucestershire | 500 |
