Sales of the iPhone in the two months immediately after its November launch in the UK fell just short of O2's target of 200,000 units.

That's according to the Financial Times, which claims that "people familiar with the situation" have said the actual sales figure "is about 190,000".

Premium phone, premium price tag

Of course, that's still a lot of handsets - and only 10,000 short of O2's original target - so it's by no means a disaster. In fact, given that some analysts like Gartner bullishly predicted up to 400,000 iPhones would be sold in the first eight weeks, the FT's figures suggest that O2 was actually lot more realistic about its iPhone venture than might have been expected.

That said, the real test for O2 during the next twelve months will be how effectively it is able to sustain interest in the iPhone, especially now that the iPhone is no longer the newest kid on the block.

After the initial rush of early-adopters and die-hard Apple fans, how much further can the iPhone's appeal extend? Is it doomed to remain a niche designer product, or can it push on and crack the mainstream market? The £269 price tag is certainly its biggest barrier, especially when UK phone buyers are used to getting their handsets for free with a contract.

A significant number of potential new customers could also be put off by O2's insistence on an 18-month contract for the iPhone. Although the basic £35 tariff, with 200 minutes and 200 texts, plus unlimited EDGE data and free Wi-Fi access is actually a pretty good deal.

New iPhones incoming?

And despite Apple's best efforts to reassure current iPhone owners, lingering fears over the possibility of a price-cut or the introduction of upgraded models (16GB or 32GB versions are rumoured, a 3G variant is planned for later this year) are likely to throw lighter fluid on any flames of doubt.

Despite an undeniably good start, O2 and Apple may need to work a little harder to keep the iPhone momentum going throughout 2008.

One recent development in the US that might help to drive sales is an announcement that AT&T is to offer a business tariff for iPhone customers.

Until now the iPhone has been primarily marketed as a consumer product. However the news of AT&T new range of business-inclined tariffs alongside IBM's rumoured announcement that its Lotus Notes eMail application is coming to iPhone, is a sure sign that the onetime 'Jesus phone' will be looking to tempt moneyed corporate clients during the coming year.