The Apple Watch Series 3, which is now available to buy from Apple, adds cellular capabilities to the mix. This means it can function as an independent device, picking up texts and answering calls when out of reach of its companion iPhone - good news for runners who like to stay in the loop.

But cellular comes at a cost. As well as adding to the price tag of each individual watch (the Series 3 starts at £329 if you plump for GPS only, or £399 if you want cellular), it requires you to sign up with a data provider.

In the UK, the only network provider that can currently set you up with a plan for the Apple Watch Series 3 is EE. (You can either buy the watch from EE on contract, or pay for it upfront from someone else, such as Apple, and then add it on to your EE phone plan at an additional tariff.)

If you're on EE already, or willing to start a contract with EE, then this is fine. But what if you've got a phone contract with a different provider? For how long will EE remain the exclusive UK provider?

Elsewhere we focus on Three and Vodafone, but in this article we examine the chances that O2 will be able to provide Apple Watch Series 3 data plans in the future, and if so, when this is likely to happen. This is based on official statements from O2, EE and Apple, on our understanding of the technical issues involved, and on past behaviour by the parties involved.

When will Apple Watch 3 LTE come to O2?

Why can't O2 offer Apple Watch data plans?

The first thing to mention is that this isn't some sort of artificially created exclusive sweetheart deal set up between EE and Apple - there is, according to EE and corroborated by one other provider, a concrete technological reason why that provider is the only one capable of handling the Apple Watch in the UK.

An EE spokesperson told us that "EE is the only UK network that has the capability to 'share' a number across a hard SIM (in the phone) and the Apple e-SIM (in the watch)."

At present this isn't something O2 can offer - so it isn't simply a question of waiting for an exclusivity deal to expire.

In this sense we think this will work out differently to the original iPhone. That device was initially available only on O2 in the UK, but it is understood that O2 won this deal by offering to return a large proportion of its revenues to Apple. That exclusive deal lasted for just over two years, before Orange were brought on board too.

If the Apple Watch arrangement was a 'pay to play' type of deal like the iPhone, one would expect Apple to have offered exclusivity for a significant length of time. But in this case the barrier is based on technology factors, not revenue-sharing ones.

Does O2 plan to cover the Apple Watch Series 3?

The company is cagey about this. We spoke to O2 and were told only that "O2 will not be ranging the Apple Watch Series 3 from launch but continues to review its range of products and services to ensure that they meet the needs of customers."

O2 has promised to keep us in the loop as and when its plans change, and we will update this article whenever we hear new information - from O2 or elsewhere. And of course, if you get wind of any relevant rumours, be sure to let us hear them.