Least cost routing.
Least cost routing enables you to take advantage of the deregulation in the Telecoms market, by making cheaper telephone calls.
There are now many companies providing cheaper calls through least cost routing.
In many cases, you could make a saving of around a third of your BT bill, and in some cases much bigger savings.
When BT was privatised, the Telecommunications industry attracted a lot of new companies to compete with B.T., which means thatthey now have to operate in a way which allows competition.
BT are required, by law, to allow you as a BT customer to "route" your calls over alternative suppliers if you wish to do so.