These bent figures are today's slaves. Their masters are the Revolutionary United Front (RUF), the rebel movement which has used diamonds to wage a war without mercy in the west African country for the past nine years.

Until his arrest two months ago, the RUF leader was Foday Sankoh, a warlord who combined random brutality - his fighters specialised in chopping off the limbs of men, women and children - with a meticulous approach to the business of diamond dealing.

Two school exercise books emblazoned with the slogan "Peace. God bless the teacher" were recovered from Mr Sankoh's villa in Freetown, the Sierra Leone capital, and obtained by the Financial Times. They record the scale of the RUF operation in the diamond pits at Kono, one of many controlled by the rebels.

The book entry shows that 220 diamonds worth about $2.5m locally were mined in a single day on 9 January 1999 at Kono. Between October 30 1998 and January 1 2000, the RUF sold 10,137 Kono diamonds through the murky channels of the world's illicit diamond market.

Government officials in Freetown think the documents prove a long-held suspicion that Sankoh's rebels sold illicit gems to buy guns - and that they were helped by neighbouring Liberia whose ruler, Charles Taylor, is a longstanding supporter of the RUF.

The link between diamond dealing and arms trafficking in Sierra Leone fits the pattern of two other violent conflicts in Angola and the Democratic Republic of Congo. In these three former European colonies, the scramble for control of the diamond fields has helped to fuel a cycle of violence, mass homelessness and economic collapse.