Travellers warned they could face unnecessary £7 a day charge unless they make this switch

Brits thinking of jetting off on holiday have been warned they must make a simple switch before flying to avoid an unwanted daily charge. Failing to check this one thing on your phone could cost you £7 a day.

You may not realise that you are at risk of paying roaming fees when abroad. Roaming charges are additional fees incurred when using your mobile phone outside of your usual network's coverage area, often when travelling abroad, meaning tourists are particularly at risk of these costs.

These charges arise as your phone connects to a different mobile network, and your provider has to pay that network for access to its service. Roaming charges can encompass extra costs for calls, texts, and data usage.

Recent research by Uswitch found that fees can be as high as £6 per megabyte (MB), meaning holidaymakers can easily rack up a big bill without even knowing it.

And, as reported by , Ofcom has warned that around 14% of UK customers had experienced inadvertent roaming.

Luckily there is a simple step you can take to ensure you're not hit with these charges. This involves turning off roaming permissions in the settings of your phone.

However, this does mean you won't be able to access mobile data services while out and about. Instead you will only be able to use the internet on your phone if you connect to WiFi.

To prevent charges coming as a shock to tourists, Ofcom has brought in some changes.

All providers are now obligated to notify customers when they become subject to roaming charges while travelling.

They also have to direct customers to free information outlining the roaming costs where they are.

Charges can vary significantly. For instance, in the EU, EE will charge £2.47 a day for 50GB of data usage, after which customers are charged £3.60 per GB.

Three charges £2 a day for 12GB data usage in the EU, with additional use billed at £3 a GB.

Meanwhile, Vodafone's fees range from £2.42 to £7.39 a day for 25GB, depending on a customer's location and the package they're on. Additional data is charged at £3.13 a GB.

Of the big four providers, O2 is the only one to offer free roaming in the EU, up to 25GB a day, with additional GBs billed at £3.50.

In total, there are seven networks that don't charge their customers to use mobile services in the EU - although they may have usage caps.

Many networks also offer roaming packages for customers travelling overseas.

But Which? has told customers to carefully think about how much data they need before signing up.

Regardless of your provider, there are simple things you can do to avoid an unexpected bill.

You could leave roaming switched off and rely on Wi-Fi services.

With Wi-Fi available in accommodation and many bars and restaurants, you may decide to cut down on your phone use while away and just use data and mobile services when you can connect.

However, if you're planning on using apps like Uber or Google Maps, you might need to think about data usage.

One option could be to purchase a pay-as-you-go SIM for your trip, but remember to check the charges before you start using it.

Alternatively, you could buy a local network SIM card when you arrive at your destination to take advantage of local rates.