Kenya’s Supreme Court has overturned the election of incumbent President Uhuru Kenyatta, in an unprecedented decision nullifying the results of early August polls due to “irregularities”.

It is the first election in Kenya’s history to be overturned and an unexpected victory for embattled four-time opposition candidate Raila Odinga, whose Nasa party petitioned the court to overturn the results.

The ruling from the Supreme Court rendered the results “invalid, null and void”, violating the constitution and thereby requiring a “fresh presidential election” to be conducted within 60 days. Mr Odinga had lost by about 1.4 million votes out of roughly 15 million cast.

Mr Odinga alleged the polls to be fraudulent and rigged against him by both the President’s ruling Jubilee party and the Independent Electoral and Boundaries Commission, the body responsible for carrying out the polling, tallying and transmission of the results. Both have denied such allegations.

The court ruled 4-2 in Mr Odinga’s favour. The court, whose full decision with details of its findings is expected to be released within 21 days, did not blame Mr Kenyatta or his party.

The move was not only a shocking blow to Mr Kenyatta, who was declared the winner on August with just over 54 per cent of the vote, but an indictment of the electoral commission and Western observers, who endorsed the election as credible and transparent.

In the weeks following the election, the electoral commission has been widely criticised for failing to produce the complete paperwork to support the electronic tally of the vote.

As the decision was announced on Friday morning, crowds of jubilant Odinga supporters outside the court broke out into cheers and political party chants. Throughout the day, supporters converged, marching from the slums – Odinga strongholds – to Nairobi’s central business district.

Kenyan election annulled Show all 13 1 /13 Kenyan election annulled Kenyan election annulled Supporters celebrate in Mathare slum after President Uhuru Kenyatta's election win was declared invalid by a court REUTERS/Siegfried Modola Kenyan election annulled Judges stand to deliver their verdict at the Supreme Court in Nairobi, ordering a new presidential election within 60 days after cancelling the results of last month's poll AFP/Simon Maina Kenyan election annulled Kenyan opposition leader Raila Odinga waves at supporters as he leaves the Supreme Court AFP/Simon Maina Kenyan election annulled Supporters of opposition leader Raila Odinga cheer outside court after President Uhuru Kenyatta's election win was declared invalid in Nairobi Reuters/Baz Ratner Kenyan election annulled Supporters of opposition leader Raila Odinga celebrate in Kibera slum after President Uhuru Kenyatta's election win was declared invalid by a court in Nairobi Reuters/Thomas Mukoya Kenyan election annulled A supporter of opposition leader Raila Odinga eats a cob of corn and does the splits as he celebrates after hearing the verdict AP Photo/Ben Curtis Kenyan election annulled Supporters of opposition leader Raila Odinga celebrate after hearing the verdict AP Photo/Khalil Senosi Kenyan election annulled Supporters of The National Super Alliance (NASA) opposition coalition and its presidential candidate Raila Odinga celebrate in front of the Supreme Court after learning that the court ruled in favor of Odinga EPA/Dai Kurokawa Kenyan election annulled Supporters of opposition leader Raila Odinga kneel down and thank God as they celebrate after hearing the verdict, on a street opposite the Supreme Court AP Photo/Ben Curtis Kenyan election annulled Supporters of Raila Odinga celebrate after hearing the verdict AP Photo/Khalil Senosi Kenyan election annulled Supporter of opposition leader Raila Odinga celebrates after hearing the verdict AP Photo/Khalil Senosi Kenyan election annulled Supporters celebrate after hearing the verdict AP Photo/Khalil Senosi Kenyan election annulled Supporters of Kenya's opposition National Super Alliance (NASA) leader, Raila Odinga celebrate in the streets of Mathare slum in Nairobi Tony Karumba/AFP

Despite a heavy police presence, celebrations remained peaceful as supporters celebrated the unexpected news, chanting “Justice has been done” and “Uhuru must go”.

“It’s incredible. In Kenya, people never believed in the Supreme Court,” opposition supporter Steven Nyai told The Independent. “For us, the long night of injustice is over and it’s finally daybreak.”

In 2013, Mr Odinga contested the election at the Supreme Court on similar grounds and his petition was overturned, upholding Mr Kenyatta’s win.

Mr Odinga himself called the ruling a “history day for the people of Kenya and by extension the people of Africa”.

Supporters in the streets told The Independent they felt the international community pressured Kenyans to accept the “sham” in order to maintain post-election peace and security.

Following a contested election in 2007, more than 1,200 Kenyans were killed and 600,000 displaced due to politically motivated, tribal violence.

Pressure from the international community was high going into the recent polls as diplomats reaffirmed the need for stability for Kenya to maintain its status as a regional economic and humanitarian hub.

Riots break out after Kenya election's contested result

Teams from the United States, across Africa, and a robust European Union monitoring mission backed the election as free and fair.

The day after the early August vote, a team of international elections monitors sent by the Carter Centre and led by former US Secretary of State John Kerry enthusiastically endorsed the electoral process calling it and urged all Kenyans to accept the result peacefully.

“We call on all Kenyans to carefully evaluate ... the details of the process the IEBC has put in place and has been painstakingly following,” the statement read. “We hope they will agree with us that fairly implemented to completion, it provides for the integrity of the election,” Mr Kerry said in a statement following the elections.

“Shame on them!” Steve Maingi, an Odinga supporter, said outside the court.

“The international community supported thieves,” Hamisi Wafula added. “It is not for people from foreign countries to choose our leaders. Now we have the justice we have been denied before.”

A joint statement issued by US ambassador Robert Godec and UK High Commissioner Nic Hailey along with other diplomats failed to address the perception that foreign pressure rushed the announcement of presidential results.

“The court’s independent review has demonstrated Kenya’s resilient democracy and commitment to the rule of law ... All electoral processes can be improved, and we will continue to support Kenya’s institutions in this important work,” the statement read.

President Kenyatta addressed the nation on Friday afternoon, calling for calm and peace amongst Kenyans but reiterating that while he respects the rule of law, he firmly disagrees with the court’s decision.

Mr Kenyatta went on to say the majority of the country is behind him and called out the justices.

“Six people have decided they will go against the will of the people,” he said in the televised address.

Later, addressing supporters in Nairobi, he lashed out, condemning the court ruling in stronger terms and accusing the judges of being in the pockets of “whites.”

Mr Odinga aimed his criticism squarely at the electoral commission, insisting the body be disbanded before a new election can take place.

“It is now clear that the entire edifice of IEBC is rotten, the four-time presidential candidate said at a press conference. “The commission was taken over by criminals ... they must face criminal prosecution.”

He repeated his call for the commission to be dissolved, adding: “We cannot repeat the election with this commission.”

The chairman of the election board, Wafula Chebukati, insisted he would not resign but promised personnel changes and prosecutions of staff members deemed to be involved with tampering of the August vote.

“To protect the integrity of [the] sovereign will of the people, the commission intends to make internal changes,” Mr Chebukati said.