There isnt a definitive list... But the place that dished them out is www.ripe.net
Bear in mind only about 80 ISP's in the UK have their own IP allocations the rest are all VISP's and borrow ISP's from the bigger people...
How to find out if an ISP has its own allocation -
Step 1 - Goto a Command prompt (Start -> Run : Type "command")
Step 2 - Type "ping www.ispwebsite.co.uk"
Step 3 - Take the IP address given - eg: 213.120.228.99
Step 4 - Visit: http://www.ripe.net/perl/whois
Step 5 - Enter the resulting IP in the box.
Step 6 - All is revealed as to if the ISP has their own IP allocation or not.
A yes - mand they run their own network, a No means they are esentially a VISP and rely on other ISP's for services.