But in a small West African state the same prized gems are responsible for almost inconceivable atrocities that have scarred the lives of millions. Diamonds smuggled out of Sierra Leoneís mines have financed the rebels fighting the state's brutal civil war.

It is a conflict that has seen some 20 000 children as young as nine kidnapped, drugged, tortured and forced to kill as child soldiers. Eight years of war have left 75 000 dead and more than 10 000 civilians as young as two with limbs hacked off as part of a savage campaign of terror by the rebels.

A documentary featuring award-winning footage shot at the height of the fighting a year ago will this week show interviews with child soldiers and civilians being shot and mothers and children being beaten.

The rebels organised boy soldiers into killing squads during an attack on the capital Freetown. When the rebels were later ejected they took 4000 children with them - boys as soldiers, girls as sex slaves.

Ibrahim Barry Junior, 16, was nicknamed General Shed Blood by the rebels and was in charge of 50 boys. Abducted at the age of nine, he was drugged and taught how to kill. He said: "I kill hundreds because I fought for long years. When I have taken my drugs I would even kill my brother. I feel happy to kill when I have taken the drugs. Sometimes I remove your heart and just chew your heart."

Ibrahim escaped and has been receiving trauma counselling. But there are only four rehabilitation centres in the country for the estimated 20 000 child combatants.

Pressure group Global Witness last year launched its Fatal Transactions campaign to highlight the role of the diamond trade in countries like Sierra Leone. Director Charmian Gooch said: “If you buy a diamond engagement ring for your girlfriend you have no way of knowing whether you are funding children having their hands hacked off or turned into child soldiers. We are not against the diamond trade as a whole. Most of it, in countries like South Africa, Botswana and Namibia, is legitimate. It is funding development and populations are benefiting. But in Sierra Leone it is widely accepted that diamonds have played a major part in funding the rebels who have committed horrific atrocities”.

The world's largest diamond company De Beers, controls the supply of 70 per cent of newly-mined diamonds through its central selling organisation in London. Referring to the rebels, a De Beers spokesman said: “It's quite possible they have been funded by the diamond trade. Smuggled diamonds may well find their way to places like Antwerp and Israel. What happens then is for the customs officers to deal with”.

The war between the Sierra Leone government and the Revolutionary United Front officially ceased after a UN-brokered peace deal in July which included an amnesty for all war crimes. But sporadic fighting continues and disarmament is yet to happen.

The Channel 4 documentary made by Insight News Television, features footage by Sierra Leonean cameraman Sorious Samura. He was the only journalist to stay in Freetown when the rebels attacked. He said: “Most of us in Sierra Leone have never seen a diamond. In the West a jewel is given as the ultimate symbol of love. But in my country rebels paid for their weapons by selling diamonds to the West for millions of dollars. It is no longer acceptable for the West to make excuses and look the other way”.