They are also optional.
1471 (& 141 & 1470) is a standard
BT 1471 – BT 1471 is free but the Call Return feature costs a fixed fee of 17.7p (applies whether or not the call is connected). Dial 141 before your call to avoid your number being obtained through 1471/Caller Display.
As is 1571:
BT Answer 1571 voicemail – The call return feature does not work with withheld or international numbers. Customers who use Call Barring (and select option 1) will not be able to use 1571. The attempted call set-up will cost 17.7p. Some social/burglar alarm equipment may not be compatible with 1571 (check with your supplier). Customers must make at least two chargeable or inclusive calls a month (or 6 a quarter) to avoid a £1.02 a month charge for 1571.
EDIT: Oh, I see! They are optional in the sense as to whether you care to dial them
1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 19 Meg WBC
Edited by XRaySpeX (Sun 22-Apr-12 00:24:36)