The high profile launch of Apple's new iPhone was hit by problems today when computer problems prevented customers buying the gadget.
Customers who queued through the night were still waiting to buy an iPhone two hours after the launch.
Hundreds of Apple fans waited inside Apple's flagship store on London's Regent Street because of a problem with network provider 02's server.
Apple staff said the sheer number of iPhone customers attempting to register with the site this morning appeared to have caused the problem.
Most customers remained upbeat about the delay although some left the store out of frustration or because of work commitments.
Antonio Guerra, 19, a London fashion student, said he queued for 17 hours to be second in line outside the store this morning.
He said at 10am: "I'm good, I've been here for 19 hours, I don't mind waiting a few more. They reckon it could take another two hours."
Another customer, Chris Moorby, 26, from London, said: "It's not ideal but that's life. I'm leaving now because I've got to go to work but I'd otherwise wait all day. I've got a lot of patience for Apple."
02 and Carphone Warehouse outlets across the UK are thought to have been affected by the glitch.
The launch of the hotly-anticipated gadget attracted thousands to stores early this morning.
02 warned yesterday that supply issues meant each of its stores would have, on average, just a few dozen of the handsets to sell today.
O2, Apple's network partner for the handset, said Apple stores were having "technical issues" connecting to 02's online systems.
A spokesman said O2 and Carphone Warehouse outlets were trading normally, although registration systems in O2 stores ran slowly for about an hour this morning.
He said: "Customer interest in iPhone has been phenomenal this morning.
"Sales are currently business as usual and we're busy selling to customers in O2 and Carphone Warehouse stores across the country. Average transaction time is about 20 minutes, as per normal.
"We can confirm that Apple stores are having technical issues connecting to O2 systems. The systems are currently working but quite slowly. We are working to get the systems back up to full speed as quickly as possible."
About 150 people waited outside Apple's London store for the 8.02am launch.
David Suen, 27, a London School of Economics student from Australia, was first in the queue.
He had been waiting since 6.30am, having bought his place on eBay for "less than £50" from a man who had been queuing since 11am yesterday.
He said: "I've been waiting for this since the last iPhone because of 3G.
"It's very exciting."
Both O2 and the Carphone Warehouse had to suspend online orders for the iPhone earlier this week, citing "incredible demand".
The updated version of the combined iPod, mobile phone and internet browser features a high-speed internet connection and GPS satellite positioning.
It costs substantially less than its £269 predecessor but is still available in the UK only from O2, Carphone Warehouse and Apple stores, and will work only on the O2 network.
O2 and the Carphone Warehouse are giving away the 8Gb version of the iPhone to customers who sign up to tariffs costing £45 or £75 a month.
The gadgets will cost between £59 and £159 for customers on other tariffs.