Kenya is to hold another presidential election after the previous poll was declared invalid by the country’s supreme court.
Judges ruled by a majority of four to two that the win by President Uhuru Kenyatta was “null and void” as a result of irregularities committed by the election board.
They ordered a fresh ballot be held within 60 days.
It is the first time in Kenya’s history a presidential election result has been cancelled.
The country’s stock exchange temporarily halted trading after blue chip shares plummeted in response to the decision.
The historic move comes after a petition was filed by opposition candidate Raila Odinga.
He had claimed the electronic voting results were hacked and rigged in favour of Kenyatta.
Concerns around the poll were fuelled after the official who oversaw the electronic voting system was found tortured and killed days before the election.
International election observers said at the time that they had seen no interference with the August poll, which saw Kenyatta win a second term with 54% of the vote.
But Kenya’s top court has now decided the poll was not conducted in line with the constitution.
Judge David Maranga, announcing the verdict, said: “The declaration [of Kenyatta’s win] is invalid, null and void.
“The first respondent (the election board) failed, neglected or refused to conduct the presidential election in a manner consistent with the dictates of the constitution.”
The court did not place any blame on Kenyatta or his party.
Odinga said: “This is a historic day for the people of Kenya and by extension for the people of the continent of Africa.
“For the first time in the history of African democratisation, a ruling has been made by a court nullifying irregular election of a president. This is a precedent-setting ruling.”
The president’s chief lawyer, AhKmednassir Abdulahi, told the court the quashing of the result was a “very political decision”, but said they would live with the consequences.
Ahead of the decision, Kenya had been braced for a repeat of the unrest that followed the August poll, in which human rights groups said police killed at least 24 people.
Security was tight around the courthouse with armed police and barricaded streets.
The legal ruling paves the way for a new race for the presidency between Kenyatta and Odinga.
Odinga has contested the last three elections and lost each time.
On each occasion he has alleged the polls were rigged.
A dispute over the 2007 poll, which Odinga challenged after being declared the loser, was followed by weeks of ethnic bloodshed in which more than 1,200 were killed.