In an email sent out to existing iPhone owners who've registered interest in the 3G model, O2 has stated that it'll be restricting sales of the new handset.

"We do expect demand for iPhone 3G to be very high so orders will be processed on a first come, first served basis so that we can be fair to all customers," it says. "Orders will be limited to one iPhone 3G per customer."

In theory, the news means that there'll be less 3G iPhones up for grabs on eBay next Friday, after they go on sale.

In practice, touts can get around this by using friends and family, while it's unclear if the policy applies across the multiple retailers who'll be selling iPhone in the UK – can one person walk into an O2 store, then an Apple Store, then a Carphone Warehouse branch and end up with three 3G iPhones?

Meanwhile, there's no news yet on O2's pre-ordering process for existing iPhone owners, who've been promised the chance to get to the head of the queue for the 3G model.

"We will be writing to you again before the 11th with details about how you could place your order," says the email.