Kgalema Motlanthe, a former trade unionist, was sworn in yesterday as South Africa's third black President.

He takes over from Thabo Mbeki, Nelson Mandela's successor, who was ousted on Sunday after losing a power struggle within the ruling African National Congress (ANC) in the country's worst political crisis since the end of apartheid in 1994.

Mr Motlanthe, 59, who remains as the ANC's deputy president, sought to calm nerves after a week of political turmoil, which Archbishop Desmond Tutu criticised as the antics of a banana republic.

The incoming President told the National Assembly that the work of the Government would not be interrupted. He was elected by 269 votes to 50 with 41 spoiled ballots in an assembly in which the ANC has a two-thirds majority.

“We will not allow the stability of our democratic order to be compromised,” he said after taking the oath of office. “We will not allow the confidence that our people have in the ability of the state to respond to their needs to be undermined.” Mr Motlanthe, who spent ten years as a political prisoner on Robben Island, announced that the internationally respected Finance Minister, Trevor Manuel, had been reappointed to his position. Investors and markets have been jittery over South Africa's political turmoil and were worried the ANC would lurch to the left.

Mr Motlanthe is only expected to be a caretaker and serve until elections in April or May in which Jacob Zuma, the ANC president, will be the party's candidate for president unless he is charged and convicted on corruption and fraud charges before the poll - a prospect that is widely dismissed now his close allies are in charge. Mr Zuma is not a Member of Parliament and could not be nominated.

Many analysts and commentators believe that the ANC could now split, with younger pro-Mbeki supporters forming a new opposition party that would seek to unite several weak groups under one banner.

A senior Western diplomat said: “I would not have believed it until recently, but I think it is a possibility now. The divisions and bitterness within the ANC run very deep, and they are not going to be able to paper over them.”

Mr Mandela, 90, was said to be monitoring events closely, but with extreme sadness. However, he has made no formal comment on what has happened - a silence that is seen as more favourable to Mr Zuma, who is hugely popular with the party's grassroots and the impoverished of the black townships.

“He is in the Zuma camp. He only had to say Thabo [Mbeki] should serve out his second term, but he didn't,” said a top ANC insider.

Times Recommends

• Peter Moore’s family say they can smile again
• Ambition always comes before a fall
• Putin: Russia needs more weapons to counter US