http://www.ispreview.co.uk/

Top ISPs By Users
No. - ISP NAME - Subscribers
1. BT Retail (2,791,000)
2. Wanadoo (2,400,000)
3. AOL UK (2,300,000)
4. NTL (2,085,000)
5. Tiscali (1,694,000)
6. Telewest BY (838,873)
7. Breathe (630,000)
8. Clara.net (450,000)
9. Brightview (300,000)
10. Pipex (250,000)