You could be forgiven for thinking that if you buy an iPhone 5 at launch you'll be able to use 4G when Vodafone, O2 and Three launch their 4G networks in the future. Sadly, this is not the case, and the 4G iPhone 5 which will be available from 21 September will not be compatible with any forthcoming networks from either Vodafone or O2.
The problem is that only EE is anywhere near having a working 4G network in the UK, and even EE has said iPhone 5 4G customers will have to sign up with Orange or T-Mobile first. It has done this by re-assigning some of its old, 2G, frequency allocation. This is happening on the 1800MHz band, which T-Mobile and Orange has used since the original introduction of GSM digital phones.
The good news for Three customers, however, is that if you buy an iPhone 5 at launch you'll get access to 4G in the second half of next year. This is because Three has bought some of EE's capacity, which will allow it to make use of 4G on the same frequencies.
The whole 4G situation is making O2 and Vodafone very cross indeed. Mainly because they think this gives EE an advantage, but mostly because both firms refarmed their 900MHz spectrum in 2011 for 3G. Had they wanted, they could have launched a similar service to EE's at the same time.
Vodafone does say, however, that it invests £1.5m in its network every day, and that it will cover 98 per cent of the population on 3G by 2015. It also claims to have better indoor coverage, something it achieved by adding 3G services on its 900MHz allocation.
In the US Apple has had the same problem with 3G. AT&T uses a GSM network, but for the phone to launch on Verizon's CDMA/EVDO network Apple had to rework the phone, and re-release. And there is every reason to expect that if, somehow, Vodafone and O2 get 4G frequencies before the next iPhone, then Apple will quite likely update the iPhone for them. It is more likely though that we won't see 4G on O2 or Vodafone until late next year: by then, the frequencies will have been approved and Apple will be able to sell a phone to that does 4G.
In the UK though, customers have got used to being able to move around from network to network. Anyone buying an unlocked iPhone 5 for its 4G abilities could very well find themselves disappointed if they hope to use it on their Vodafone or O2 contract. We suspect the problems with 4G won't be communicated well to the person on the street, leaving him both confused and angry.
So, for the love of all things gadgety, don't buy an unlocked iPhone 5 expecting it to work on your network, because you'll just end up using 3G. If you're not going to be an EE or Three customer, you're far better off waiting for Apple to introduce a new handset that supports 800MHz and 2.6GHz, the frequencies Ofcom is planning on releasing for 4G.
We can't blame Apple for any of this. Global frequency allocation is a nightmare, pure and simple, and it doesn't look like it's going to get any better. The only saving grace is that phone radios get more advanced every year, and eventually phones will probably end up supporting dozens of them. But not this year.
Based on the iPhone 4, it's a fair bet that the iPhone 5S will have support for all the UK 4G frequencies and you'll be able to buy an unlocked one, and use it on any network you like.