I’m indebted to Paul Atkinson for alerting me to this plug. Ordinary UK mains plug USB chargers, like the one supplied by Apple, are a bit awkward to pack. I have been using a MU folding plug for travel. However this plug from Amazon folds down neatly and has two USB outlets (rather than the single of the MU), one of which is a fast charging port. Although it’s a bit heavier than the MU (55g vs 42g), it’s a lot cheaper at £3.99.
I’ve been using it for a week now, and it has worked perfectly. I was slightly concerned that, being so cheap, it might be defective. However, it’s been fine. It’s useful to have two USB outlets for charging a phone and another item simultaneously. If you’re looking for a USB travel charger, it’s worth considering.
Disclaimer: this plug was purchased with my own money