UK travelers to the EU, and vice versa, could lose free roaming
privileges on their mobile phones if Brexit becomes a reality.
and no longer escaping mobile roaming charges for Brits traveling
to the UK, and for European Union citizens traveling to the UK,
could be one of the components. Were leave voters thinking of that?
— Dennis Schaal
Source: FS – All-Travel destinations-News
Brits Could Lose Free Mobile Roaming When Traveling to EU