That's what I meant by threatenNo, not if you just "threaten" - you have to actually give notice (which you can cancel if you chicken out). My wife tried "threatening" last week, and the best they would do was £10 a month off - but she had to sign up again for a whole year. We'll go through the process of giving 30 days notice after the forthcoming series of Game of Thrones.
Worth checking out the later pages on this huge thread: http://forums.moneysavingexpert.com/showthread.php?t=2652651&page=209
Don't know how they get away with their prices. We joined years ago in the analogue days, but the market has changed so much with Netflix etc.