From the Ofcom announcement:
Mobile phone companies will be banned from selling ‘locked’ handsets, under a range of new rules from Ofcom that will make switching even simpler.
Some companies – including BT/EE, Tesco Mobile and Vodafone – still sell mobile phones that can’t be used on other networks unless they are unlocked. But this is a potentially complicated process which can also cost around £10. Our research shows that more than a third of people who decided against switching said this put them off. Almost half of customers who try to unlock their phone have difficulties doing so. For example, they might experience a long delay before getting the code they need to unlock their phone; the code might not work; or they could suffer a loss of service if they did not realise their phone was locked before they tried to switch.
So, following consultation, 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. The new rules will come in from December 2021.
The ban on selling locked handsets is part of a package of measures we’re introducing, most of which reflect new European rules. This includes making switching easier and helping to make sure customers are treated fairly. Under the new measures announced today, you will also be able to get a summary of the main terms of your contract in writing – before you sign up. This will include things like the length of the contract and prices, and broadband providers will have to tell you the minimum internet speeds you can expect from your service.
That's still a year away, but I welcome the move and it's notable here not just for your own phone-buying future, but also for that of your family and those who depend on you for guidance(!)
I've always advised that it's best to have (vastly cheaper) SIM-only contracts and then source your own SIM-free handsets. It sounds as though these new rules will even out the marketplace, with more emphasis on the actual voice/data tariff and less on paying for a (locked) phone over a year or two. Which is good and potentially less confusing all round.