BT unveils call screening phone, for any provider.

[#1]

BT unveils call screening phone
Could this be the answer?
It will be available to households who do not use BT as a provider also.
http://www.guardian.co.uk/money/2013/feb/06/bt-call-screening-phone-bt6500-silent-calls
Other options mentioned

[#2]

It doesn't sound like it does anything Truecall doesn't. However, it will be good to have a bit of competition as Truecall's price has remained at a high level long after its initial launch.

[#3]

Locked in favour of http://community.plus.net/forum/index.php/topic,111746.