Botswana's high court on Tuesday dismissed petitions filed by the main opposition parties against the election result that returned the Botswana Democratic Party (BDP) to a parliamentary majority.

The BDP of President Mokgweetsi Masisi won the election in October with 38 seats – automatically making their candidate president – while the opposition Umbrella for Democratic Change (UDC) got 15 seats, and two smaller parties got four between them.

October’s election was the first time there had been any doubt about whether the long-ruling BDP would return to power, after a spat between Masisi and former President Ian Khama, who backed his rival, seemed to throw the contest open.

“On the face of the petitions, it cannot be deduced that the people or institutions which allegedly committed the corrupt and illegal practices are election or polling agents,” Justice Mercy Garekwe said. “The petitions are therefore a nullity.”

The ruling party has been in power since independence from Britain in 1966, and the country has enjoyed stability and prosperity thanks to its plentiful and well-managed diamond resources.

But its over-reliance on those same diamonds and high unemployment are now major policy challenges for its leaders.

At his swearing-in last month, Masisi promised to drive a transformation of Botswana's economy that would create more jobs for its 2.2 million people and diversify the economy away from minerals.