Call Protect is rubbish, it doesn't actually "block" anything. In fact, Openreach internally refer to the feature as "Choose to Divert"- a far more accurate name. Calls are still connected (thus ensuring vital revenue for BT); your phone just doesn't ring and Caller Display is somehow bypassed as well. Other than that, it's not much different from the standard 1571 Voicemail service. It's inconvenient for the user as well, because you have to keep dialling 1572 to see if a voice message has been left that just might be important (at least 1571-compatible phones will check this for you and send an alert, or you hear the stuttered dial tone when you pick up the receiver which tells you there's a message waiting). Also, you can't deactivate the Voicemail element of Call Protect, which is an absolute pain! You also can't review your list of blocked numbers and unblock them using your telephone keypad - you have to do it online (not good for those without a 'My BT' account, which is most of those who only take a phone service from BT), whereas Choose to Refuse (see below) lets you do it over the phone (by dialling 14258). With Call Protect you can only "block" the last number that rang as well, whereas Choose to Refuse allows you to manually add a number.
Choose to Refuse and Anonymous Call Reject are two features that have been around for many years and do the job properly by physically blocking calls at exchange level so that they are NOT connected at all, in any form. So, although expensive, they are extremely effective and well worth the money (and available free with Line Rental Plus or Home Phone Saver). This is why my parents cancelled Call Protect and went back to the tried-and-tested pairing of Choose to Refuse/Anonymous Call Reject (Call Protect is incompatible with the latter two, they cancel each other). I have to say that ACR is more valuable than CTR, as CTR only allows you to block 10 numbers; it would be far better if BT followed TalkTalk's example and expanded that to 100 numbers (the maximum permitted with Call Protect). But clearly they have no interest in expanding/improving the feature and want to wind it and ACR down, no doubt having convinced themselves that Call Protect is a worthy replacement.
Call Protect is certainly no better than those so-called "call-blocking" phones, which are now very common (and at least such phones allow you to deactivate callers' ability to leave a message, unlike Call Protect, meaning that Call Protect is inferior even to those).
