According to a few old posts around the web (circa 2010) BT Infinity had a fair use limit of 300GB/month after which you'd get traffic shaped.
According to their current website however, this seems to have changed as it specifically states:
Code:
Is traffic management used to manage compliance with data caps and download limits?
No
Is traffic management used in relation to heavy users?
No
Can anyone confirm/deny this means it's now completely unlimited (or are they just pulling the wool over my eyes?)