UK customers have grown used to the idea of the 'locked' smartphone that can be used with only one network, but Ofcom has announced that the practice's days are numbered.

"Following consultation," said the telecoms regulator in a press release, "we have confirmed that mobile companies will be banned from selling locked phones. This will allow people to move to a different network with their existing handset, hassle-free."

If you had to explain phone locking to an alien, it would sound quite odd, and incredibly unappealing: the idea of buying a handset that can only be used on a single network - unless you buy your way out, jump through hoops to get an unlock code, or quite often both. And removing this barrier obviously makes it easier to shop around for a better deal, and increases competition.

But I would also try to explain to the alien the link between phone locking and discounted handsets. If a network can't lock you into using their service, it's much less appealing for them to give you the phone at a loss. Of course, it's harder to justify networks keeping you locked in after you've completed (or paid the remaining balance on) the original contracted period.

It's unclear at this point how the new regulations will affect the sale of discount handsets. You would still be obliged to pay down the balance of the contract if you jumped ship early, so in theory the carrier is just as well off as before. But a cynic might suggest that carriers bank on at least some users baulking at the inconvenience of switching even after the contract is finished, and inconvenience should no longer be a factor.

So this is good news, generally speaking, even if the secondary effects have yet to become clear. And it's worth tempering any soaring spirits with the news that it's not happening until the end of next year. December 2021, to be exact.

More than that, as Barry Collins points out, there's more than a hint of EU involvement; indeed it's hard to imagine that the generally timid Ofcom would have been so bold if it didn't have to comply with the European Electronic Communications Code.

In the meantime, for assistance dealing with the rules as they are now, read our articles on How to check if an iPhone is locked, and How to unlock an iPhone.