UK mobile operators are now banned from selling unlocked phones to their customers, making it easier for consumers to switch providers in search of a better deal.
Traditionally, phones provided under contract were tied to a particular network with carriers forced to unlock those devices at the end of the customer's minimum term.
However, this can be an inconvenient process. If an unlock code is delayed or doesn't work, there is a potential loss of service, while some people may not realize their device is locked.
This situation means that many people choose to negotiate a new contract with the same operator when they could be better served elsewhere. Others stay at the same rate, paying too much because they've already paid for the bundled item.
Some carriers, including O2, Sky, Three and Virgin Media, had already changed their practices to offer unlocked phones as standard. However, Ofcom decided that a more formal intervention is needed.
It said last year that the additional costs and actions required to unlock a device are unacceptable and inconsistent with its desire to boost competition in the UK mobile phone market and make switching providers as easy as possible. Now the rules have officially come into force.
Other measures taken by the regulator include the possibility of changing the operator by sending a single text message. Operators must respond to a cancellation SMS within a minute with a PAC code that allows customers to keep their existing phone number with another network, removing one of the biggest barriers to switching.