Martin Lewis issues warning as people can now be charged £6 daily for using phone abroad

The Money Saving Expert, 50, said that after Brexit, a lot of mobile phone companies will be introducing roaming charges.

Prior to this, mobile networks were banned from charging customers extra for using their phones in the EU.

While some mobile companies don't have roaming costs in Europe, some have changed their 'fair use' policy, which means that you won't be able to use your data abroad in the same way that you can in the UK. For example, networks can cap your roaming data allowance below what you’d get at home.

Martin Lewis is now warning people to check how their providers regular their daily roaming charges as it can be vague.

"I've no faith in mobile firms to self-regulate," he said, as reported by The Mirror. "When we left the EU, they promised not to reintroduce European roaming charges… yet most of the big networks have broken that promise. So our report calls on Ofcom to not trust voluntary promises – we need to reintroduce the formal, compulsory consumer protections.

"And it's time too, to define time. We need to ban a daily roaming fee charged for use 'up to 11.59pm' without even mentioning in which time zone. Instead, we recommend all providers must define a roaming 'day' as a 24-hour period from first use, clearly explain that in the arrival text, and alert customers at least an hour before the daily charges end."

An Ofcom spokesperson said: "Ofcom is currently considering the options for future roaming protections for customers, looking at the risk of consumer harm and how to best protect customers in this area. We will take these findings into account as part of this process."

This includes advising people to use free WiFi as much as possible, and depending on the length of your stay, considering investing in a local sim card.

It's also recommended that you don't opt out of your network usage cap, as this could have particularly expensive consequences when you use your phone abroad.