The iPhone is out of stock in Carphone Warehouse and O2 stores amid allegations the handset has become a target for box breakers.

Apple’s CFO Peter Oppenheimer has reportedly admitted the iPhone has been a target for box breakers.

O2 and Carphone confirmed they were out of iPhone stock praising the £100 price promotion, but neither would comment on box breaking being a cause for the high levels of demand.

A spokesman for Carphone Warehouse said: ‘Our price promotion has given many more of our customers the opportunity to enjoy the iPhone experience. 

‘Due to this unprecedented demand we have now sold out of the 8GB iPhone and we're currently reviewing the stock situation.’

Store staff from both companies told Mobile  a lot of iPhone box breaking had been going on since the price dropped by £100 to £169, some £75 less than the European price tag.

Unlockers told Mobile they have witnessed a sharp increase in the numbers of devices being brought to them for reprogramming since the price cut.

One Carphone store manager said: ‘O2 will probably find a much lower percentage of iPhones will go live than when they still cost £269.’

A spokeswoman for O2 said: ‘We have been delighted with the response to our iPhone price promotion which has surpassed our expectations.

‘Owing to this success we are currently out of stock of the 8GB iPhone. Customers keen to get the iPhone experience can purchase the 16GB iPhone at the standard price through O2 channels at the standard price of £329.’

Separately, O2 confirmed that customers who bought a full-price iPhone two weeks or less before the price drop would be given a refund of £100.

The iPhone running out of stock along with the apparent reluctance of Carphone and O2 to replenish numbers is fuelling rumours of an imminent release of a 3G version of the device.