An escalating land-rights conflict in Botswana threatens to tarnish the reputation of one of Africa's best-governed countries.

At the weekend police arrested 21 people as they tried to enter the Central Kalahari Game Reserve. The group included Roy Sesana, an activist member of Botswana's Basarwa minority - commonly known as Bushmen - leading a court case against Botswana's government to seek the right to live in the reserve.