We got our monthly BT bill today, which we don't normally check as it's only for line rental and is usually for the same amount - £10.99.
Lucky we did check it - there was a 'One off charge' of £1.48+VAT and no explanation of what it was for.
Phoned BT and after waiting for about 10 minutes on hold, was informed that it's the monthly charge for Caller ID (which we don't use because our handsets don't support it!). We asked them when they told us about this, and they said it should have been on our last bill (which it wasn't - we'd checked before calling), The chap on the phone apologised and said that he would refund the charge. We told him that we didn't want caller ID at all, he said it's still free if you make 2 chargable calls on BT each month - which we don't as all our calls go through Virgin.
Aswell as the above, small print on the second page of the bill advises that from 01.03.2007 (7 days ago), they will start charging as above for the 1571 service at £1 per month - so we've ditched that service too!!
So everyone who still pays BT for line rental only - CHECK YOUR BILLS!! as they have started applying charges all over the place!:x
(They've also applied new terms and charges to customers wanting to leave BT!!)