The O2 iPhone page simply says '8GB and 16GB are no longer available'. We knew the 8GB model was no longer available after a price reduction, but had no idea that the 16GB version was in short supply.
Alas, the 'Find out more' button merely links to a page about iPhone tarriffs.
Apple, meanwhile, is still selling the EDGE iPhone models via the Apple Store - so presumably they have some remaining stock to shift before the 3G announcement, which is expected at the WWDC in San Francisco next month.
Thanks to eagle-eyed reader James Coldwell for spotting this one - we'll have response from O2 just as soon as they arrive in the office...
UPDATE 13.15BST - you can read O2's slightly unconvincing response here