What is inadvertent mobile roaming?

Mobile in handInadvertent roaming happens when your mobile phone switches to a neighbouring country’s mobile network even though you haven’t crossed the border.

It can be a particular problem for people living and working close to the border between Northern Ireland and the Republic of Ireland; causing them inconvenience and forcing them to pay higher rates for their mobile calls.

Inadvertent roaming happens because the radio signals used by mobile networks do not simply stop at international borders. 

Mobile phones will pick up the strongest available signal and in some border areas that may not be your home network. 

While improving coverage of UK networks in border areas can help, the problem of inadvertent roaming can never be completely removed.

What is Ofcom doing about the problem of inadvertent mobile roaming in Northern Ireland?