EVERY time you switch on your mobile, power up your laptop or even switch on a light, you could unwittingly be fuelling slavery, civil wars and human rights violations thousands of miles away.

Our humble domestic appliances, electronics and jewellery can be a final link in a brutal chain linking Western democracies to militias and terrorists in far-flung corners of the globe, from Burma to Colombia and the Democratic Republic of Congo (DRC).

The common ingredient is "conflict minerals" - and European legislators, led by Scotland, are seeking to eliminate them from our supply chain. Like blood diamonds, conflict minerals are sourced through opaque or illegal practices in unstable areas of the world.

They include gold, tungsten, tin and tantalum, a rare mineral extracted from coltan ores mined in conflict-riven countries such as the DRC and Colombia. Once mined - often in appalling and dangerous conditions by poor locals intimidated into slave labour - they are sold on, generating profits for whichever rogue group controls the territory.

Earlier this year, the European Commission published draft regulations to help clamp down on the use of conflict minerals by targetting smelting companies, but there has been criticism that compliance would be voluntary and would not cover products which already contain conflict minerals when they are imported into the EU zone.

In comparison, the United States is introducing laws which will ban conflict minerals from the DRC from the supply chain - though detractors point out that this fails to tackle the illegal trade in other nations.

Now Alyn Smith MEP, the Scottish Member of the European Parliament's foreign affairs committee, has written to chief executives and the directors of senior tech firms asking for confirmation that their products are sourced from ethical materials. Smith wants to highlight companies adhering to ethical procurement routes and to expose those that are not.

"I have had hundreds of constituents contacting me asking for my support on tackling this issue," said Smith. "The European Commission is working on setting up a voluntary self-certification system for importers but I think we can - and must - do more. In areas such as the DRC, tin, tantalum, tungsten and gold are sourced in conditions of extreme exploitation, violence and slavery. According to the International Peace Information Service (IPIS), armed groups are present at more than half of all mining sites in the DRC, where the local population is illegally coerced into working in the mines and controlled by rape and violence.

"Many Scots will find it shocking that the ores of the 'three Ts and gold' can be found in everyday items ranging from mobile phones to hearing aids.

"Conflict minerals are a little-understood facet to procurement and it is positive that the world is waking up to the fact that we may be complicit in modern-day slavery.

"I want to see a mandatory scheme where compliance is visible to consumers and applicable all along the supply chain."

Companies including Apple and Hewlett-Packard have already disclosed their mineral supplier lists voluntarily, and Intel vowed its new microprocessors would be free from conflict minerals. However, other electronics giants such as Nintendo - the world's largest manufacturer of videogame consoles - have been criticised for being less transparent.

In 2013, the EU imported around 240 million mobile phones. There is about 6.6g of tin, 830mg of tungsten, 40mg of tantalum and 630mg of gold in a standard mobile phone. That means that an estimated 1,584 tons of tin and 151 tons of gold entered the EU as part of mobile phones alone in 2013.

But the minerals find their way into a vast array of goods, from electronics and cars to laboratory equipment and weapons.

In Colombia, conflict has cost more than 218,000 lives, seen between 4.7 and 5.7 million people displaced, and resulted in the forced disappearance of over 25,000 people. Tantalum and gold mines and the associated trading routes there are controlled and taxed by armed groups - either directly, or through lucrative protection rackets which force mining companies to pay rebel forces.

The Revolutionary Armed Forces of Colombia (Farc), the main group involved in illegal mining activities, derive up to 20% of its economic resources from control of Colombia's gold trade, in addition to cash flow from drug trafficking and kidnappings. Other groups such as the ELN and BACRIM profit from the trade to a lesser degree.

In mining areas, control over land has become increasingly militarised and 80% of Colombia's human rights violations occur in areas where minerals and oil are extracted. Local people are lured into the work by the promise of earning up to £400 a month while risking their lives in deathtrap conditions and inhabiting crowded, plastic shanty towns.

Mark Campbell, a programme manager for the Scottish Catholic International Aid Fund (Sciaf) in Nicaragua, Colombia and El Salvador, has been working in Chocó in north-west Colombia for four years.

Despite having the country's richest mineral resources it is the minority Afro-Colombian communities who suffer under increasing poverty as a result of the corruption.

"A lot of the miners are local people who, given the lack of economic opportunities in the region, are forced to work in these mines," said Campbell. "The region is historically a mining region and for a lot of the communities, their main activity traditionally has been panning for gold. But a lot of these rural communities have been forced off the land and then work in the mines as a way of making an income. The mines are basically just big holes dug straight into the riverbank and on the edges of that you've got the shacks for the workers, made of wood and plastic and nailed together - very basic. There's not even sanitation."

Americo Mosquera, legal representative of Cocomopoca, a collection of 43 Afro-Colombian communities which have been fighting to have the rights to their ancestral land recognised for more than a decade, said: "The armed groups come after the illegal mining as it is their source of finance. They do better getting their resources from mining than by filling a truck with cocaine.

"When the owners of diggers come to mine in an area that belongs to an armed group, the first thing they are told is: 'You have to give three or four million pesos to come into the area'. So you can see a relationship between illegal mining and the armed groups.

"The local community leaders are afraid to stand up to the armed groups and tell them what they think, because it is difficult to face somebody when they have a gun in their hand. The presence of armed groups has been a destabilising factor for the communities."

In the DRC, trade in tantalum, tin, tungsten and gold has funded the civil war between government forces and rebel groups for well over a decade, as they fight over control of the mines and funnel the profits back into the conflict. Local people are caught in the crossfire, intimidated and enslaved into working in the mines, with the minerals they dig up only helping to perpetuate their bondage. The civil war has already claimed more than 5.4 million lives since 1998.

Myanmar (formerly Burma) is another country rich in gems and precious metals but dogged by accusations of human-rights violations at the hands of its national army, the Tatmadaw, which controls the mining industry, as well as its associated marketing and export operations.

The Burmese military has one of the worst human-rights records of any army in the world and regularly faces credible allegations of killings, torture, rape, forced labour and forced displacement.

Sciaf is among the humanitarian organisations and charities now demanding tougher action from the EU to outlaw conflict minerals entirely from the products bought and sold within its jurisdiction.

Jo O'Neill, policy officer for Sciaf, said: "From our work on the ground in countries like Colombia and the DRC, Sciaf has witnessed how the global trade in minerals - like gold and tin - is fuelling violence, instability and misery.

"While the proposed legislation is a welcome recognition of this problem it must be strengthened if it is to meaningfully address the suffering of communities; this means replacing the voluntary proposal with binding requirements, compelling European companies all along the supply chain to source minerals responsibly.

"MEPs and Member States have an important opportunity to ensure companies do not profit from conflict. It must not be missed."