Shoppers are queuing across the UK this morning to get their hands on the latest must-have Apple iPhone.

The demand for the new version of the phone is so high that retailers have warned that they are unlikely to meet the demand. The phones are on sale at about 1,300 Apple, O2 and Carphone Warehouse stores.

O2, Apple’s network partner for the handset, has warned that each store has only a few dozen iPhone 3Gs to sell today. Some shoppers may have to wait until the end of the summer for phones.

A message on O2’s web site said: “We are experiencing unprecedented demand for the device and while we are confident that all customers who want iPhone 3G will get one by the end of this summer, initial supply is limited and will be for some weeks.”

The updated version of the combined iPod, mobile phone and internet browser has a high-speed internet connection and GPS satellite positioning.