A WATCHDOG has called on mobile phone companies to unlock handsets for free after finding that charging customers can act as a barrier to switching.

Which? has launched a campaign to help consumers "unlock better mobile deals" after a survey revealed just four in 10 (40%) trust their provider to put them on the best deal for their usage at the end of their contract, and many think it is unfair that phones are locked to one provider.

Which? is calling on all mobile phone providers to offer the unlock service for free at the end of a contract and at point of sale for pay-as-you-go phones.