The world’s first fair-trade smartphone will be unveiled to the public in London this week, marking a leap forward in ethical technology. The Dutch firm behind the phone said it had worked closely with pressure groups to ensure the smartphone, called Fairphone, was the most ethically sourced product available.

Smartphone makers such as Apple and Samsung have in the past been criticised for failing to reveal that their products were made from resources mined in conflict zones and manufactured in Far East factories where labour practices have been called into question.

The new handset, with a screen size of 4.3 inches (10.9cm), half-way between the iPhone 5 and Samsung Galaxy SIII, will retail at £272, but is not available until December. Almost 15,000 have already been pre-ordered. Potential customers will be able to handle the new product at the London Design Festival on Wednesday

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A number of minerals used in smartphones often come from conflict zones, such as the Democratic Republic of Congo (DRC). The three Ts – tantalum, tin and tungsten – in particular, are extracted from mines in the region and armed groups controlling them are alleged to benefit, with profits fuelling the fighting.

Fairphone’s tin and tantalum are extracted from conflict-free mines – those where profits aren’t used for the purchase of arms.

Product manager Miquel Ballester said he decided to start building a fair-trade phone rather than simply campaigning against existing phones because “it would be too easy to stand by and criticise others”. The business started out as a campaign for fair wages and working conditions across the supply chain of smartphone makers, but evolved into a social enterprise. “It’s only as a manufacturer that you’re playing by the same rules as the big brands. Then you can have real impact,” he said.

Mr Ballester is using tin from mines in South Kivu, in eastern DRC, despite on-going fighting among militias for control of the mineral trade, but insists that the company is working hard to ensure its workers are fairly treated and the profits don’t get into the hands of the militias.

“The whole point of the Fairphone social enterprise and the campaign that came before it is to intervene on the ground where the problems have originated,” he explained.

In contrast to Apple’s sealed devices, the Fairphone handset can be opened by consumers and is easy to repair, extending its lifespan. It runs a custom version of Google’s Android operating system, built by the London-based developers Kwame Corporation. One innovative feature is a dual SIM card slot, which allows for business and personal phones to be merged into one, reducing the number of devices in circulation. This is a common feature of phones in Africa and Asia.

Mr Ballester admitted that Fairphone is not fully ethical, but claimed this was not the point. “With the classical social auditing of manufacturers that’s been done for the past 20 years, you can tick a few boxes and earn a certification, but once you turn around and leave the factory there’s nothing to stop things from changing. For us, it’s about creating a business environment that favours ethical treatment from the outset.”