What about charges for international data roaming services such as 3G?

A dongle plugged into a laptopUsing your mobile internet, or ‘data’, connection to go online overseas can cost considerably more than it does at home – particularly outside Europe

In the European Union (EU),  the maximum surcharge that an operator can impose (on top of its domestic data prices) is €0.05 (around 4p) per MB of data, excluding VAT.

However, the cost of data roaming can be significantly higher outside Europe – often around £6 – £8 per MB of data.

You can even run up a big bill without actively using your phone as smartphones and 3G/4G enabled tablets automatically seek out mobile connections and use them to update apps.

So unless you turn off data roaming before you go, these devices could be downloading data at standard rates throughout your stay without you realising it.

There is a safety net – all mobile operators have to apply a cut-off limit once you have used €50 (excluding VAT) – around £40 – of data per month, wherever you travel in the world, unless you choose to opt out.

To find out more - including advice on how to turn off data roaming on some of the most popular handsets - check out our guide on using your smartphone or tablet abroad.