Justice Maraga said the election commission had failed "to conduct the presidential election in a manner consistent with the dictates of the constitution".

?He said the commission had committed irregularities "in the transmission of results", adding that the court would provide details in a full judgment within 21 days.

Dissenting judges said that the Nasa opposition alliance - which had petitioned the Supreme Court - failed to prove claims that the polls had been rigged.

The election sparked days of sporadic protests, in which at least 28 people were killed. The vote had raised fears of major political violence - as was the case after a disputed poll in 2007.

Eoin Treacy's view

Governance is Everything. The annulment of Kenya’s election is a landmark event but the true measure of a democratic society is whether the opposing parties can agree to another election and accept the result without resorting to what could be cause for a civil war.