Sky Mobile to offer flexible contracts with rollover data

It's been a long time since Sky revealed plans to become a mobile virtual network operator with the help of O2. The company opened up registrations for Sky Mobile last month, not that those registering really knew what they were expressing their interest in. Today, though, Sky has pulled the curtain aside on its upcoming mobile offering, which will finally go live in mid-December. It would be unadvisable to enter such a saturated market without a unique selling point to pitch, which in Sky Mobile's case, is rollover data and fully flexible contracts.

Just as BT favoured simplicity when it reentered mobile last year, Sky is starting out with just three SIM-only plans.

You'll notice we've only highlighted data allowances in the table above, because that's all you get. Calls and texts are either billed on a pay-as-you-use basis -- each minute or message costing 10 pence -- or you can throw down an additional £10 per month for the unlimited package.

A Sky Mobile contract comes with a 12-month term, but you're not agreeing to any fixed pricing structure. Each month, you can change your data plan, and add or remove the unlimited calls and texts package. You can do this mid-month, too. Say you're on the £10, 1GB tariff, and are running out of data. You can upgrade to the £15, 3GB tariff, pay the fiver difference, and immediately get those two extra gigs. The next month, you can drop back down to the 1GB plan again and just pay £10.

This flexibility and competitive pricing, at least where data is concerned, isn't even Sky Mobile's killer feature -- data rollover is. Any unused data, from any month, goes into your "piggybank," which you can draw from to top up your allowance at any time. Now, any rolled-over data does expire after three years, but the piggybank works on a "first-in, first-out" basis, so you withdraw the data that will expire soonest, first. A family can link up to five SIMs with a single piggybank, too, so what the parents don't use, the kids can eat through later. All plans and piggybanks are said to be easily managed via a mobile app or online.

The whole point of being a quad-play provider, which Sky will soon be, is so you can cross-pollinate your other services with alluring customer incentives. Thankfully, how this works in Sky Mobile's case is relatively simple to explain. Existing Sky+ TV customers that pick up a mobile contract get the £10 unlimited calls and texts package for free, and they also get Sky Go Extra for free.

To jog your memory, Sky Go Extra is a mobile app that lets you download content for offline viewing and stream live TV on the move. Sky Mobile subscribers will get one new feature, though, called "Sync." Sync effectively lets you see what's sitting on your Sky+ box at home, helping you decide what you might want to catch up on when you're not sat in front of the living room TV. Sky is selling this as the best features of Sky Go Extra, with the added discovery features of your Sky+ box.

And that's it for now. There are currently no incentives for Sky broadband customers, and no word on how that might play out if/when Sky get around to it. Either way, we're told the plan is to keep everything as simple as possible, especially when Sky Mobile expands into handsets from the likes of Apple and Samsung sometime next year.

The launch schedule is probably the most complicated thing about the whole proposition. Contracts will initially be available to anyone who registered their interest ahead of time -- more than 46,000 people, apparently -- and existing Sky TV customers. Only Sky+ customers for now, though, since they're the only ones that can take advantage of this new Sync feature.

Sky Q customers, and anyone else, will have to wait until the "full market launch," which will start early next year.