The Kenyan government has rejected the choice of Cyril Ramaphosa, a South African who played a leading role in talks to end apartheid, as chief mediator for negotiations with the opposition on ending the crisis in the ­country.

The move raised new questions over the government’s commitment to reaching a settlement, as Mr Ramaphosa had been selected by Kofi Annan, the former United Nations secretary-general, to manage discussions on the most contentious subjects.