The launch of the iPhone 4 has generated more interest than any other mobile release in its history, according to O2.
According to the network, which had exclusive rights to sell Apple phones in the UK until last year, double the number of punters hit its high street shops on the day of release for the newest iPhone than turned out last year for the 3G S.
Matthew King of O2 said: "The big challenge for us now is getting enough stock to meet continued significant demand and we're as frustrated as our customers when it comes to getting our hands on them."
In the three years since the iPhone's launch, O2 has sold three million iPhones - a figure yet to be matched by any other handset, according to Mr King.
This week the carrier posted operating profits of £736 million for the most recent quarter - a year on year increase of eight per cent.
Profits at parent company Telefonica were up by nine per cent to nearly £3.2 billion.