Cambodia’s outgoing leader Hun Sen has marked his 71st birthday with official confirmation of his party’s landslide victory in last month’s election.

Electoral officials said on Saturday that his ruling Cambodian People’s Party (CPP) had swept 120 of 125 seats.

Critics called July’s poll a sham after the main opposition, the Candlelight Party, was banned on a technicality.

But the result allows Hun Sen to proceed with a plan to appoint his son as his successor in the coming days.

Hun Manet, 45, was until recently the commander of the Royal Cambodian Army and has long been groomed for the role. The transition was first flagged in 2021, but until July it was unclear when the change of power would occur.

Saturday’s confirmation that Hun Manet had been elected an MP removed the only remaining procedural hurdle to his taking office.

His father is now expected to ask the King to appoint him prime minster on Monday. Hun Sen has said the succession is designed to maintain peace and avoid “bloodshed” should he die in office.

He is expected to become president of the Senate early next year and will serve as acting head of state when King Norodom Sihamoni is abroad.

Since he came to power following the fall of the murderous Khmer Rouge regime four decades ago, Hun Sen’s rule has become increasingly authoritarian.

He has consolidated power through control of the military, police and moneyed interests. Observers say he has dispatched opponents through co-opting, jailing or exiling them.

Indeed, there was little doubt over the result of last months poll, with some critics branding it more like a coronation than an election.

The Candlelight Party, Cambodia’s main opposition and the sole credible challenger to Hun Sen, was disqualified from contesting the election in May after officials accused the party of filing incorrect paperwork.

Apart from the CPP, the royalist Funcinpec Party took five seats, while the remaining 16 opposition parties all failed to gain any representation.

The CPP took 6,398,311 votes from a total of 8.2 million ballots cast, or 78% of the popular vote. Before the poll, the government criminalised any attempt to boycott the election or spoil the ballot papers.

The US, EU and other Western nations refused to send observers to the poll, saying it was neither free not fair.

EU officials said the vote was “conducted in a restricted political and civic space where the opposition, civil society and the media were unable to function effectively without hindrance”.

Hun Manet celebrated Saturday’s result by posting a photo to Instagram showing his young son presenting Hun Sen with a bouquet of blue and yellow flowers, captioned with the message: “Happy birthday to respected and beloved father”.