Apple has agreed to install a 'kill switch' that will make stolen mobile phones worthless – dealing a huge blow to the booming trade in snatched devices.The tech giant announced a change in the settings on its phones worldwide following a campaign led by Britain's top policeman and backed by the Daily Mail.The move allows the devices to be shut down and rendered unsellable – and comes after London became notorious as the global capital of phone theft.Scotland Yard Commissioner Sir Mark Rowley announced he was writing to the Home Secretary asking for legislation to force them into making stolen mobiles unusable. The black market is worth more than £50million a year in the UK, but will the 'kill switch' end the phone snatching epidemic? Vote in the Mail's latest poll here:

In yesterday's poll, Mail readers were asked: 'Should passport checks be conducted between Northern Ireland and the Republic?' Out of more than 12,000 votes, 90 per cent of you said 'yes' and 10 per cent said 'no'.