When reports emerged of people being electrocuted by third-party adaptors when charging their iPhones, fatally in one case, Apple responded by opening an adaptor take-back programme in the US and China. Take an unauthorised or counterfeit USB power charger back to an Apple store or service provider and you can buy an official adaptor for almost half price.
Now Apple is about to extend that offer to other countries around the world, with the UK scheme opening on 16 August. You will be able to swap any USB charger you aren't sure of for an Apple one for £8. The usual price is £15. You also have to take your iPhone, iPad or iPod touch with you to prove you own one.
Other countries to get the programme from 16 August include Japan, Germany, Australia, Canada and France.
The service will end on 15 October for all regions, so if you suspect you've bought a dodgy power supply, you have until then to get one guaranteed to work. Apple won't tell you if the supply is unsafe or not as testing procedures are too lengthy, it will just swap it regardless.
You can find out more on Apple's support pages.