O2 claims it has already sold more iPhone 3G S handsets than it did on the launch day of the iPhone 3G.

O2 spokeswoman Emma Hart confirmed that the higher sales were not due to the registration issues that marred the launch of the iPhone 3G. She said: "Last year we had a slower processing time for the first hour, but by 10am we were up and running fine. We are confident we processed as many customer as we could that day."

The mobile phone network described seeing 10 times higher than average footfall in its stores during the launch morning, leading it to anticipate selling 50 per cent more iPhone 3G S handsets than it did on launch day for the iPhone 3G.

Hart went on to confirm that the company was confident it would be able to meet demand for the iPhone 3G S. "We have been through the experience before so we are able to anticipate stock levels, and replenish them quickly."

"We are delighted with the sales of iPhone 3G S, we will be refreshing stock in stores overnight for the weekend with a further delivery early next week," added Hart.

Hart suggested that existing O2 customers may have a perception that it is easier to upgrade their mobile by going straight to O2. "If a customer has an existing contract with O2 they may have the perception that it's easier to upgrade with O2. They can come into the store and talk tariff options though. Maybe talking to O2 directly makes sense," said Hart.