I'm not quite as optimistic as others.
1) Not sure about BT but Sky, for example, do specify it very clearly in their small print that Sky Talk, Sky Broadband and Sky line rental are all covered by separate contracts, so technically, if a price is changed and a change is detrimental, you could only get out of that one contract, not all three
2) It is Ofcom's regulation I think that you can leave a contract early if there is a detrimental change, but some ads by some ISPs mention in the small print that prices may go up "at any time" during the contract. Not sure what the implications are re leaving contract penalty-free, I usually stay away from such ISPs
3) Let's not forget that it's BT, where customer service is <...> and any arguments and common sense are ignored by the person on the other end of the phone, plus, as tier 1 CSR's they don't have the authority to make decisions on such things anyway if their script says otherwise.
So, bottom line - read the cancellations part of the contract before agreeing to anything, especially over the phone.
And - have no doubts, the line rental will increase. They have done it every year up to now, and they are not in a position to skip a year now, given their business rates situation.
Edited by Mml (Sun 20-Nov-16 18:29:43)