Former gold miners in South Africa can go ahead with a class action against mining companies over health damage allegedly caused by their work, a court in Johannesburg has ruled.

The high court decision paves the way for what would become the largest class action in South African history.

The ex-miners say they contracted silicosis, an incurable lung disease, from years of working in the mines.

The court said that a class action was "the only realistic option".

Judge Phineas Mojapelo's decision could lead to a court case lasting up to 10 years, the BBC's Nomsa Maseko reports from Johannesburg.

But she adds that the former miners hope that, if successful, the case could help improve their lives as well as those of their families.

Silicosis, caused by inhaling silica dust contained in gold-bearing rocks, can lead to breathing difficulties, regular coughing and chest pains, and it can also lead to tuberculosis.