If competition in a market is not effective, then regulation may still be required. Customers can be called from anywhere in the UK at a local call rate. The caller pays the local rate and the customer pays the balance. Customers can be called from anywhere in the UK at the national rate. The caller pays the full national rate and the customer pays nothing.
Callers pay for the cost of the call together with a variable charge for the content of the call.
Customers earn revenue from the calls.