Cameroon’s president, Paul Biya, on Sunday will mark 40 years in power, making him the second-longest ruling leader in Africa after Equatorial Guinea's Teodoro Obiang Nguema Mbasogo, who seized power in 1979.
The 89-year-old is also believed to be one of the world’s oldest rulers, and his increasingly rare appearances in public have stoked concerns over his health.
But any talk about who might succeed Biya, who turns 90 in February, is strictly taboo in government circles.
‘Ministers have fallen into disgrace just for thinking about a theoretical departure of the president,’ says Aimee Raoul Sumo Tayo, a Cameroon defence and security specialist.
In private, however, conversations abound, with commentators saying none of the potential candidates enjoys unanimity, and not one of the most visible figures around the president has publicly stated any wish to succeed him.
Biya assumed office as president on 6 November 1982, after seven years as the country’s prime minister, becoming only the second head of state since Cameroon’s independence from France in 1960.
Commentators say his extraordinary political longevity can be ascribed to a mixture of astuteness and ruthlessness. He has a close-knit group of loyalists who hold key positions, and crushes or sidelines opponents and rivals.
The Cameroon People's Democratic Movement, founded by Biya in 1985, says it will be holding a big party across the country to mark his 40 years in office.
At its headquarters in Yaounde, party members are selling caps, scarves, shirts, and multi-coloured garments emblazoned with Biya's face ahead of Sunday’s main event, a ‘mega-rally’ to be held in the capital.
It will be a celebration of ‘political stability and peace, the biggest successes of these last four decades in Cameroon,’ says a member of the party's central committee, Herve Emmanuel Nkom.
But there is no word as to whether Biya himself will be attending the festivities.