Voters in Botswana have rejected the country’s long-serving governing party in a result that marks a political earthquake in the diamond-rich southern African nation.

The Botswana Democratic Party (BDP) – in power since independence in 1966 – had won only one parliamentary seat as of early Friday morning, preliminary election results show.

The Umbrella for Democratic Change (UDC), led by human rights lawyer Duma Boko, won 20 seats, according to the early tallies.

UDC looks set to form the government as it is projected to pass the 31-seat threshold for a majority in parliament.

As MPs elect the president in Botswana, Duma Boko is on course to become the next head of state once parliament meets for the first time.

Boko, who is running for the third time, has urged his supporters to “maintain vigilance and discipline”.

Despite overseeing a dramatic change in Botswana, recent poor economic growth and high unemployment dented the BDP’s popularity.

He will replace Mokgweetsi Masisi – in office since 2018 – who led the BDP’s failed campaign.

The president ran on a message that his party could bring about “change”, but not enough voters were convinced the BDP could do what was needed for the country.