From the effective date of withdrawal, in the event that there is no agreement establishing other conditions, the United Kingdom will become a third country for the purposes of EU roaming rules (Regulation (EU) No 531/2012). This will mean that mobile phone users can stop benefiting from the obligation that their phone providers now have to not apply any roaming surcharges to them, if those providers decide to voluntarily modify their rates or the application of surcharges.
In case of agreement for an orderly withdrawal, the roaming surcharge would not be applied during the so-called transition period. Implementation after the transition period is over will depend on the future relationship agreement between the United Kingdom and the European Union.
In the event that telecom operators do not give sufficient advance notice of possible price changes in roaming rates or telephone calls to or from a fixed or mobile telephone in the United Kingdom, the user may file a claim with the Office of Telecommunications User Support.