There are reports of queues forming in some of Vodafone's 400 high street stores, despite the fact that the company's pricing is scarcely different from the tariffs offered by O2 and Orange.
In November last year, Orange brought O2's two-year exclusive deal with Apple to an end and started stocking the iPhone itself, selling 30,000 on the first day.
Tesco followed suit last month but has not given any sales figures. This week the supermarket announced its best Christmas trading figures for three years. It has been moving aggressively into the telecoms market and has more than two million customers of its Tesco Mobile venture, which uses O2's network.
The company said this week that one customer activated their Tesco Mobile handset every two seconds on Christmas Day, while the arrival of the iPhone has "generated strong customer demand".
There had been fears that Vodafone customers would defect to Orange or Tesco, lured by the iPhone. But when Orange announced it had succeeded in wresting the device from the clutches of O2, Vodafone executives scrambled to get their own deal signed with Apple in order to prevent any defections.
Vodafone UK chief executive Guy Laurence said the company has today shipped more than 50,000 iPhones to customers, citing "exceptional demand.
Originally posted at: Guardian.co.uk