Flanked by police officers Apple staff effectively closed the London Apple Store today in the middle of the afternoon.

Garbed in blue T-shirts the Apple crew blamed the closure on UK iPhone carrier O2’s faulty registration system, as entry to store browsers was forbidden and no more customers were allowed to join the queue to purchase the new iPhone 3G.

At 3pm, customers at the world's largest Apple Store were told that it would take at least three hours to buy an iPhone, and anyway the store was closed for new business as the company couldn’t be sure that it would be able to serve the numbers already snaked round the store.

“The O2 system just keeps turning on and off,” explained one Apple Store staffer.

He said that Apple - unlike its retail partners O2 and Carphone Warehouse – did have stocks of the sought-after white iPhone 3G, but that customers should wait a few days for the O2 system to be repaired.

Police helped Apple staff besieged by potential iPhone customers being turned away.

Note prophetic sign in the Apple Store window.