A new smartphone has been launched in London that comes with two screens, and could enhance battery life.

The YotaPhone2 is the first mainstream product launch from Russian firm Yota, and while it has the now traditional front screen associated with smartphones, it also comes with a 4.7-inch e-Ink screen on the rear of the phone.

E-Ink is the same technology used in e-readers like the Amazon Kindle, and requires less energy to power. It also never turns off as its particles require no energy to keep them static, and little energy to refresh and move, so users will be able to check their notifications without ever touching the phone thanks to the rear display.

YotaPhone chief executive Vlad Martynov said: "When we really started believing that this was a big thing was when we got the first functional prototype in our hands.

"When you see the display start changing and interacting, and you start realising this is amazing, you can do so much with this technology; that's the moment we started believing it's the next big thing because a thousand other ideas come into your mind - what if we change mobile marketing? What if we change education? And this is really amazing for such a simple thing."

The rear screen of the YotaPhone can be used to mirror anything from the front screen, including the camera viewfinder, giving a low energy version of the entire Android software to users in order to save battery.

A special app called YotaHub is also in place that enables users to select the widgets that appear on the rear of the device, displaying notifications without the user ever having to touch the phone.

The screen can also stay active on a single frame after the battery runs out, so a map or address can be displayed if users still need it.

Using the phone's low energy mode, YotaPhone said it is possible to get 100 hours, or five days worth, of use out of the phone and that 15% battery life will last for eight-and-a-half hours with low energy active, as opposed to one-and-a-half hours with it off.

Mike Lowe, reviews editor at gadget website Pocket-lint, said: "A dual-screen smartphone was always going to divide the crowd. Compared to the original device, the YotaPhone 2 represents a significant step forward, and, as much as we thought we'd be crying 'gimmick', that e-Ink display does have genuine uses.

"From at-a-glance notifications to reading e-books, the ability to mirror Android - with some ghosting bugs at present - means even the Kindle Android app is available.

"However at £555 it demands a flagship price without dipping into the next-generation hardware or quite delivering a flagship experience overall. An interesting concept, but a niche one."