In doing so he surpasses the record of King William IV who took over from his brother, George IV in 1830, aged 64 and 310 days.
Last year the Prince of Wales appeared to joke about his long time in the wings.
The future King quipped: “I’ll run out of time soon. I shall have snuffed it if I’m not careful.”
He was speaking about a renovation project, but many people took it as a subtle reference to the widely held notion that he might be impatient to fulfil his destiny.
In 2011, Charles became the heir to the throne who spent the longest time waiting to ascend, overtaking his great-great grandfather, Edward VII.
The Queen, now 87, has indicated on several occasions that she is unlikely to follow the example of some of her European counterparts and abdicate. Queen Beatrix of the Netherlands and Belgium's King Albert both stepped down this year in favour of their heirs.
The monarch, who enjoys excellent health, may well live to be 100, given that the Queen Mother lived until 101. That means that her son would reign in his 80s.
Commentators have suggested that it is difficult to be waiting to begin the job you've trained for all your life at a time when others are contemplating retirement.
Yet, the Prince seems more content now than at any time previously. His family is growing and he seems delighted with the grandson Prince William and Kate Middleton have given him.
He has a loving marriage with Camilla that is full of laughter and shared interests.
Meanwhile, during the Diamond Jubilee he expressed his admiration for the Queen's commitment, addressing her as "Mummy" he talked about how proud she made him to be British.