Jacob Zuma, leader of South Africa’s ruling party and the country’s president-in-waiting, faced a fresh threat to his authority on Wednesday when senior figures in his African National Congress indicated they were planning to form a breakaway party to contest next year’s elections.

The schism was led by Mosiuoa Lekota, a former defence minister, and is seeking to latch on to disaffection among supporters of Thabo Mbeki, whose nine-year presidency was brought to an abrupt end by the Zuma faction last month.