Nearly all calls to premium rate BBC lines will cost a maximum of 15p under a new cap.

The corporation says it has introduced the rule to be clear to viewers. It comes after months of controversy and broadcasters being fined millions of pounds for misleading phone-ins.

The BBC does not make money from premium-rate lines and the new cap will only affect shows, such as Strictly Come Dancing, that have until now upped prices to raise cash for charity.

Shows directly related to charity appeals such as Comic Relief and Children in Need, which have also charged more for calls, are the only ones not subject to the new cap.

Director general Mark Thompson said: "BBC programmes do not make money from premium rate calls and we've always told viewers and listeners the costs of calling to enter competitions or to vote. But I want this to be even clearer.

"In future, audiences can be clear that these calls will be capped at 15 pence unless they are directly related to a charity appeal.

"I do understand that this will mean that slightly less money will go to the charities as a result of the new policy, but we're already talking to them about other ways of supporting their work."