Next King Of England? Prince Charles, At 69, Takes Over Key Duties From Queen

As Prince Charles celebrates his birthday Tuesday, he'll have spent five years as the oldest heir to the British throne for 300 years.

But his role in a ceremony remembering the U.K.'s war dead on Sunday showed that he is taking on ever-more responsibility in preparation for the moment he is crowned king.

Charles is now 69. In 2013, when he turned 65, he overtook William IV, who was King in the early 19th century and was 64 on his accession to the throne.

The oldest heir ever was Sophia of Hanover who died aged 83 in 1714. But Charles will likely be the most senior British monarch ever crowned—Sophia never actually made it onto the throne before her death.

Charles's mother Queen Elizabeth II, who has reigned for 65 years, and her husband Prince Philip, have been gradually stepping down the scale of their public duties in their old age.

Philip has now formally retired from public life, although he does attend some official events.

The Queen remains in place as Britain's head of state, but at the age of 91 has recently delegated several appearances to other royals such as Charles and his son Prince William.

One major milestone came on Sunday at the annual remembrance day ceremony, where Britain commemorates its war dead.

For decades the Queen has played a central role in the ceremony, laying a wreath for the fallen on the Cenotaph military memorial in central London. She has missed the occasion only when travelling on official business, as well as during two of her pregnancies.

But on Sunday she asked Charles to lay the tribute on her behalf, in a moment instilled with huge significance by the British press.

It is understood that the Queen wanted to watch from the balcony of Britain's foreign ministry so that she could be by Philip's side, who in line with his retreat from public life was watching from the sidelines.

And Charles will again represent his mother at the 2018 Commonwealth Games in Australia.

As Charles prepares for his accession, he faces reigning over a potentially turbulent period for Britain and its monarchy.

Brexit, Britain's departure from the European Union, is likely to have unexpected consequences for years to come.

Meanwhile New Zealand, currently ruled over by the Queen, elected a new Prime Minister Jacinda Ardern this Fall who considers herself anti-monarchy.

Charles himself is less popular than some other members of the Royal Family—which still enjoys widespread support as an institution.

A poll in September reported in The Times found that just one third of Britons believe the 69 year old heir has been beneficial for the royal family, and less than a tenth thought his influence had been "very positive," compared to almost half who delivered a very positive verdict on his son William.