The latest speculation has been stimulated by BT's purchase of a block of LTE spectrum with BT itself making the usual noises about "exploring opportunities", "strong position in WiFi to build on" etc.

So what is it going to do?

Nobody knows, but we do know that now (or hereabouts) is probably an excellent time to make a radcal move into the mobile market.

Perhaps BT's greatest asset is the fact that it doesn't have a high maintenance, middle-aged (and rather short of breath) mobile network of the sort it sold off to Telefonica, blocking its own room for maneouvre. If it did it would be trapped in the high-cost, high-priced nightmare faced, in various ways, by its big peers in both Europe and North America.

Despite Europe's large mobile network executives' continual grumbling about increasing regulation and declining ARPU, the fact is that they are all sitting on a time bomb of their own making. So successful have they been at propping up their suspiciously similar tariff structures over quite a long period of time that their business models are exposed. Each big incumbent is now worried that a competitor will morph to become a "data challenger" and will hit their markets with a low-cost proposition(s) designed to appeal to the cash-strapped austerity customer,

That is what happened in France when Free radically undercut the big three operators over a year ago. The French market is still in shock.

This point in the technological cycle, with the apparent LTE inflection point passed and the continuing rise of WiFi (see - Shock result: WiFi beats LTE user experience) may be the best time to strike.

Now with its sliver of LTE spectrum, the UK's still dominant landline operator is reported to be in talks with all and sundry to see how it could put together something innovative - probably building on its already considerable WiFi investment.

What could it be? Often mentioned is a capacity sharing deal. In this scenario BT might put its spectrum on the table and trade it for some sort of advantageous MVNO arrangement with an existing network to handle voice calls and 'cold-spot' data coverage.

In the mean time (or soon, with a little more investment) it might look at engineering its WiFi network to be the heavy-lifter and the LTE partnership the solution the network turns to when its own WiFi can't cut it.