Nine people have been killed in clashes between rival unions at a South African mine owned by leading platinum producer Lonmin, police have said. The dead included two policemen attacked by a mob, and three workers killed by officers, at the mine in North West province, police said. The violence is linked to a battle for membership between a new and a long-established trade union. South Africa has most one of the most unionised work forces in the world. It is also the world’s biggest platinum producer, accounting for three quarters of global output. There has been a surge in inter-union violence at mines recently.

Earlier this month, another firm, Aquarius Platinum, briefly shut one of its shafts after an attack that left three dead and at least 20 injured.