The world's oldest president - 13 years Trump's senior and makes Putin look like a kid

The world is full of elderly leaders, perhaps proving the saying that "with age comes wisdom". Donald Trump - the President of the most powerful nation on Earth - is 79 years old, while his counterpart in Russia is a youthful 73 by comparison.

Not to be outdone is China's all-powerful leader Xi Jinping, who turned 72 this June. However, the world's oldest president is to be found neither in North America, Asia nor Europe. That accolade goes to Africa's Paul Biya - the current President of Cameroon, although he may soon not be for much longer.

The 92-year-old veteran politician became the fifth Prime Minister of his country in 1975, serving until 1982.

He was then sworn in as President on 6 November 1982 and has been in power ever since.

Biya is seeking another seven year term, but may have to make way for his opponent Issa Tchiroma Bakary, following a contested election that has left the country on tenterhooks.

Protests have rocked cities in Cameroon after the October 12 poll was marred by irregularities, including ballot-stuffing.

Judges on the Constitutional Court have rejected calls for a re-run of the election, saying they will announce the results on Monday.

The 76-year-old Bakary has unilaterally declared himself the winner, claiming to have secured about 55% of the vote, based on what he said were returns of 80% of the electorate.

His claims have been dismissed by President Biya's supporters and loyalists. Last year, Biya was rumoured to have died after he was not seen in public for a number of days.

The Cameroon government denied the rumours, insisting the President was in good health and in spending time in Geneva.

He was eventually filmed arriving back in Cameroon from Switzerland on October 21, squashing once and for all talk of his demise.