The new feature, called Wi-Fi Calling, was first announced by EE yesterday, and is now available on Apple's smartphone for the first time; on the iPhone 5C, 5S, 6 and 6 Plus. It is the first in Europe consumers will be able to make use of the technology, first announced in the US as part of the iPhone 6 launch last year, and which is designed to provide coverage to make calls and send text messages when users have no mobile phone signal - in homes or office.