Smartphones are wonderful when one is abroad, except for two things: (a) data-roaming charges; and (b) battery life.

Problem (a), oddly enough, can be eased by buying some kind of ‘booster’ package. (T-Mobile, for example, offers 50MB for £10, and there may be better deals available from other networks for all I know.)

Problem (b) is a bigger deal: my iPhone 4 can can’t manage a long day when it’s providing full-on connectivity.

I have some friends who are BBC reporters. The iPhone seems to be standard issue for them, because they use it as a voice-recorder, among other things. One day I noticed that their iPhones seemed clunkier than mine, and so investigated.

What I discovered is that they use a Mophie Juice Pack to ensure that their phones don’t die because of lack of power. The case has an inbuilt, rechargeable battery which can be switched to recharge the iPhone when its battery dies.

I got one.

It does what it says on the tin and is a really neat solution to a real problem. Sure, the phone is bulkier (see pic below). But it means that when I’m away from base for 24 hours or more I no longer fret about battery life.