'Ashamed of your mobile?' asks Paul Merton's overpaid voiceover on the Phones 4U advert. Read on, and you may well find you have good reason to be.

Mobile phones are directly responsible for the biggest war in African history, destroying World Heritage site rainforests and driving rare gorillas to extinction.

In our consumer society, we don't often consider the full history of the things we consume. It feels like stuff just appears in shops, then it disappears when we put it in a bin. This effect is magnified when we buy something with no idea what it's even made from.

The stuff we're craving most these days is consumer electronic goods. Playstations, DVDs, PCs, mobile phones and the like. Because these gadgets are dinky and lightweight, it might seem like they're not resource-intensive to make.

In fact, making them lightweight has given new problems for engineers. Fortunately for them there's a substance called tantalum to make capacitors out of. Tantalum is a refined metal that stays stable at very high temperatures, it's the only thing capable of making such tiny electronic gadgets work so well. It's in every computer and processor-chip device.

All these amazing gadgets from MP3 players to heart monitors, from in-car GPSs to automatic shop doors, they all use tantalum, and yet it is running out at an ever-increasing rate.

We sometimes wonder what the best computers will be like in a hundred years time. The answer may well be 'about 40 years old'.

Tantalum is refined from an ore called columbite-tantalite, or coltan for short. Coltan is only found in few places on earth. By far the largest amount, some 80% of the world's reserves, is in central Africa. Some 80% of that - two thirds of all the coltan on earth - is in the Democratic Republic of Congo.

The Democratic Republic of Congo (DRC) is a massive country straddling the equator with vast rainforests, home to a range of diverse and rare wildlife. The forests in the east of the DRC are the last home of the Eastern Lowland gorilla. These forests have been declared National Parks and UN World Heritage sites on account of their amazing and precious ecology. They are also right on top of all that coltan.

Tens of thousands of people have moved into the National Parks and have dug out the riverbeds, panning for coltan. This has poisoned the waterways on which much of the wildlife depends. Such huge numbers of new human residents also need food, and with few other sources many supposedly protected animals - including the eastern lowland gorillas - are being killed for meat.

Ten years ago there were 17,000 of the gorillas in the wild. Since the war and coltan mining, the population halved in five years, and has halved again in the subsequent five years to around 5,000 today, and the numbers are falling.

Coltan mining in National Parks is completely illegal, of course. Which not only means it is working outside of environmental considerations, but outside of human rights and safety considerations. In February 2002, 36 miners were killed when a shoddily excavated riverbank collapsed on them. The illegality of the mining has allowed the controlling militias to use child labour and forced labour, and turn to other illegal trades, such as ivory. In the Kahuzi-Biega National Park all but two of the 350 elephant families disappeared in three years. Two tons of tusks were traced to the area in late 2000.

Around a third of children in eastern DRC have abandoned education in order to mine for coltan. And you can hardly blame them. If vast reserves of diamonds were found a few inches under the North Yorkshire moors, how many of us would still respect the National Park? The blame for this has to rest primarily on the shoulders of those who make coltan so valuable, and that's the people who buy it. That's us.

And whilst the miners get more than they would at any other trade available to them, the real money is made by those who trade in coltan. The traders have to be people of real power. Nearer the consumers, that's wealthy Western corporations. At the mining end of the chain, military leaders from DRC have been running the trading. Huge parts of eastern DRC have been invaded by Ugandan and Rwandan militias, who then take the coltan out and sell it from their own countries.

The war that started ten years ago in Rwanda has never stopped in central Africa. Indeed, it has expanded, drawing in troops from at least 10 countries, from Zimbabwe in the south to Libya in the north. It has left tens of millions of people dead. Its effect on Africa is akin to that of the First World War on Europe.

And it has been intensified, prolonged and largely funded by money Westerners have paid for Congolese coltan. The UN described coltan trading as 'the engine of the war,' confirming that all parties are using coltan as their funding source.

The World Bank has praised Uganda for the way its economy is doing well under WB advice (curiously, they don't praise Argentina, who also followed WB advice to the letter and to economic collapse and social chaos). But the revived Ugandan economy is based entirely on stolen minerals from the DRC. Since its troops went into DRC in 1998, Uganda has suddenly started exporting phenomenal quantities of gold and diamonds. In the year after Uganda invaded the DRC, 'Ugandan' coltan production went up 2,800%.

Much of this money was swiftly converted into weapons for what was still inaccurately called the 'civil war' in DRC. Our desire to play make believe wars on Playstations was deepening the real war in central Africa.

As concerned westerners began to understand this, the hi-tech companies were quick to distance themselves. Ericsson, Intel, Nokia, Motorola, they all assured us they never used tantalum made from traders selling Congolese coltan. Given that their suppliers are a bunch of warlords and their friends, how could they trust their assurances? Outi Mikkonen, communications manager for environmental affairs at Nokia said, 'all you can do is ask, and if they say no, we believe it'. No further checks were made.

The chain of supply is so convoluted that no electronics buyer can ever be sure of where the raw coltan came from. Each shipment can have a dozen or more intermediary owners between the mine and the consumer.

One of the major tantalum refiners is German company H C Starck, who assure us 'H C Starck is not being supplied with material from the crisis areas of central Africa'. They get their raw coltan from a number of sources, including the British-based A&M Minerals & Metals, who said 'it would be silly for us to try to pretend that we know the origin'. They did say, however, that they buy their coltan in Uganda.

So, talking about exactly the same supply, we go from 'we know, and it's none' to 'it would be silly to say we know,' with a nudge-nudge that they do know and it is indeed Congolese.

In December 2002 a peace deal was signed between the governments and militias fighting in DRC. Whilst this promises an end to the colossal bloodshed, it does not provide a solution to the environmental and social problems caused by coltan mining. (Indeed, in contravention of the peace deal, the fighting is still going on in the eastern DRC because of the coltan mines). The same brutal military leaders run the operations, using the same sites and methods of mining. The people of DRC stay impoverished and starving, while 40% of their children die in infancy.

Now there's the supposed peace in DRC, no companies have to obscure the routes for Congolese coltan, the trade can be formalised, hastened and expanded. This means the land over the reserves and the wildlife it supports will meet with an even quicker end. The only thing that can stop it is a drastic and immediate reduction in the demand for coltan products.

Unfortunately, there's another use for tantalum. Its ability to stay stable at high temperatures means it is not just the only metal for computers. It makes it the ideal material for covering things that are going to get hot by flying very fast; the Bush administration is going to need a shitload of tantalum for the Star Wars project. George Bush Sr has foreseen this and is already on the board of Barrick, a Canadian mining conglomerate and third biggest buyer of coltan on earth.

Even so, the bulk of the tantalum market is, literally, in our hands in the form of the latest hi-tech gizmo. The pressure on the hi-tech companies to stop using Congolese coltan had been based on the war in DRC. The environmental impact is also more than enough of a reason to stop using Congolese coltan.

In the UK last year we threw away enough mobiles to fill the Millennium Dome fourteen times over. On average they were 18 months old, and most of them still worked. So, if we all kept our phones for three years, we'd halve the phone makers use of tantalum.

We have to stop being seduced by pointless upgrades. We have to ignore Paul Merton's goading of us to be 'ashamed' of a phone that works, we have to resist Nokia telling us that owning one of their gorilla-killers is 'a declaration of independence' (expensive consumer goods are actually a declaration of dependence).

Technology should not be a fashion accessory, and this is infinitely more important with technology that uses destructively produced materials like coltan.

Eastern Lowland gorillas, with whom we are a cousin species equally evolved from a recent common ancestor, face extinction. As the UN says, it would be 'the first great ape to be driven to extinction - a victim of war, human greed and high technology'. To remove such a wonderful intelligent species from earth forever is not worth any amount of Playstation 2s or mobile phones.