Fairphone 3 is a sustainable smartphone, according to the company behind it. The materials are recyclable, Fairtrade and designed to be long-lasting, while the electronics don't focus on out-and-out performance; instead, Dutch-based Fairfone ensures the source is via supply chains from conflict-free locations.

Fairphone is setting up an initiative to improve the sourcing of cobalt, one of the key minerals used in electronics, while the phone has responsibly-sourced tin and tungsten, recycled copper and plastics, and Fairtrade gold. Fairphone says the handset has also been designed with repairability in mind, though that's a tough ask for most phones.

• Which is the best mid-range phone under £400?

The phone also features that former Nokia-staple, a replaceable battery. The handset runs on Android 9 Pie, and has 12MP rear and 8MP front cameras, too. Based around Qualcomm's Snapdragon 632 platform with 64GB of storage, the €450 (around £407, $499) handset does carry a premium compared to many mid-range phones. 

Fairphone is being offered by Sky Mobile. The Fairphone 3 will start at £21 a month on a Swap 24 plan, or £30 a month on Swap 12, which offers unlimited calls and texts. You can pre-order from Sky Mobile now, and it'll ship from 3 September.