Filed on October 28, 2018 | Last updated on October 28, 2018 at 11.25 am

The details have been revealed in a new biography.

A new biography of Prince Charles, the heir to the British throne, has revealed that the prince regretted marrying Lady Diana and called it a 'massive mistake'.

Prince Charles was married to Lady Diana for 15 years. They got married at the St Paul's Cathedral in London on July 29, 1981 and parted ways (got divorced) on August 28, 1996. The divorce took place a year before Lady Diana passed away.

According to a report in the Mirror, the 69-year-old future king of England said that he let the Royal family, himself as well as Diana down by marrying her. He also added that he has serious doubts about the wedding which reduced him to tears and that his proposal to Diana on February 3, 1981 felt like a 'call to duty' to her.

They happened to meet each other on 12 instances before going ahead with the wedding.

Robert Jobson, the man who has been the royal reporter for 30 years, is the one to reveal these sentiments. Jobson had been on the official tours with Prince Charles for almost 18 months and has also written a book on him.

The royal reporter has disclosed that Prince Charles had been apprehensive about marrying Diana, during the meetings that they had before the wedding. Charles happened to realise the unsuitability of their relationship by means Diana's acts of crying or 'staring blankly' at the prince when he would narrate the details of his day to her. He found also it extremely difficult to deal with Diana's temper and mood swings.

Diana suffered from uncertainties about the wedding too and Price Charles' Father, Prince Philip, asked him to either marry Diana or leave her.

The couple had two children, Prince William and Prince Harry.

The wife of Prince Harry, Meghan - the Duchess of Sussex, is pregnant with the couple's first child due in the spring of 2019.

As the heir, Charles has for years been reading the red boxes of official state papers that are also examined by his mother, shadowing her work in preparation.

As Prince of Wales, Charles is outspoken on topics such as the environment, architecture, farming and youth skills.

His activism is partly fuelled by knowing that his time is limited and he will be unable to do so as king.

Royal author Penny Junor, an expert on Charles and Camilla who recently wrote "The Duchess: The Untold Story", said the prince was in no rush to become king.

"I don't think Charles is itching to get his hands on his mother's duties. He has a very full life already," she told AFP.

"He really enjoys what he does. When he becomes king, he can't be so hands-on."

Junor said it was the queen, not Charles, who was driving the process of handing over duties, and would progressively be "more and more realistic about what it is that she can do".

(With inputs from AFP)