Very fancy speed test...
http://www.speedtest.net/
To the point speed test...
http://www.bandwidthplace.com/speedtest/
Mine is 'great' but I knew that already, BT is always going to provide the best service... remember that every other provider depends on them!
Ian try this link... should help you
http://www.youtube.com/watch?v=_ekIIvfyfD8