Carrier Pre-Select (CPS)

Carrier Pre-Select (CPS) is a service which enables you to route your fixed line calls to a telephone company other than BT in order to reduce your costs

The calls are still carried over BT lines to the CPS company's network, but at substantially reduced costs. However, if you use CPS and then ask BT to change anything at all on your BT account, they will usually disable the CPS service, and calls will revert to being billed by BT. If you think that this sounds unfair, we would agree with you - but it still happens with monotonous regularity, and OfCom don't seem to want to do anything about it. If you use CPS and you subsequently ask BT to make any changes, however minor, always check with your CPS provider that the service is still in place.