Sales of the iPhone in the UK might not have been the runaway success Apple and O2 were hoping - some have estimated that they've shifted a mere quarter of what was planned - but greater analysis will have to be put on hold as Apple has silenced the carrier from revealing the actual number of iPhones sold.

Head of media relations at O2, Simon Lloyd, has told Register Hardware that, thanks to a clause in the sales agreement, they are unable to release accurate figures until Apple gives them permission; all he would tell them is that sales in the fortnight preceding Christmas were "in line" with expectations.

Carphone Warehouse, who sell the iPhone in the UK, have confirmed that they too are contractually prevented from disclosing sales figures for the handset.

It is uncertain whether this is to prevent the premature reveal of statistics Steve Jobs will quote at the Macworld Keynote tomorrow, or a longer-term gag designed to control rumors that the iPhone is struggling in the difficult UK market.