The decision to cut £100 off the cost of the iPhone on Wednesday has boosted sales, with O2 and Carphone Warehouse stores around the country selling out of the device.

O2 stores in Newcastle, Birmingham and London say that they sold out of the iPhone on the day of the price cuts.

And an employee in Carphone Warehouse’s flagship store on London’s Oxford Street said sales had doubled from 30 per day to 60, while another Carphone staffer commented: ‘We usually sell one or two a day, but yesterday we sold about 20 – it was like launch day again.’

O2 stores are expecting more of the devices to be delivered over the weekend.

Although the price reduction took some analysts by surprise, it has been seen as a necessary move to boost sales, of what many believe was an overpriced device, before the 3G version of the iPhone is released later this year.

Ben Wood of CCS Insight said: ‘The lack of iPhone subsidies has been one of the primary barriers to its adoption.

‘In European markets where the iPhone is available, most potential buyers will have regularly upgraded their mobile phone to high-tier models and rarely paid for the hardware.’

The temporary price adjustment is subsidised by O2 and is not expected to be copied by Apple stores, where the device is still on sale at the original price of £269.

On Wednesday the 8GB version of the Apple device was reduced from £269 to £169 until 1 June. The 16GB version is not included in the offer, and remains on sale for £329.