The strict rule everyone had to follow at the late Queen’s New Year’s Eve party

When it comes to the festive season, people like to stick to certain traditions - and the Royal Family are no different.

From surprisingly simple Boxing Day treats to the one Christmas food tradition they avoid, a royal Christmas often followed similar routines and habits - and that extended into the New Year, including the same New Year’s Eve party thrown at Sandringham Estate by the late Queen.

Queen Elizabeth II’s former private secretary, Sir William Heseltine, when interviewed for the book, The Royals in Australia, revealed everyone, including family, staff and even the Queen herself, would have to follow the same rule that meant everyone had to stay up until midnight.

In the book, when describing how Her Majesty was known to be something of a night owl, Sir William explained that “nobody felt it right to go to bed before the Queen did.”

While staying awake until midnight was likely no bother on New Year's Eve, Sir William did also reveal in the book that one particular royal had an issue keeping up with the Queen's night owl habits.

Princess Diana, he is quoted as saying per Business Insider, would find the late evenings 'agony'.

'There'd be an hour or so in the sitting room of everyone sitting around making conversation and Diana was driven to such extremes that she'd excuse herself and go to bed, which was thought to be rather bad form, going to bed before the Queen.'

After staying awake to count in the new year, New Year’s Day typically followed a similar routine each year for the royals.

They would usually go to church at St Mary Magdalene Church, and spend the rest of the day enjoying some quintessential countryside activities, like horseback riding or shooting.

After New Year’s Day, it was very likely many members of the family set off back to their own homes, but the late Queen would stay put at Sandringham.

It’s understood that the late Queen would stay at Sandringham Estate following Christmas well into the New Year. In fact, she’d reportedly stay and keep the decorations up until February 6, the anniversary of the passing of her father, King George VI.

While the NYE party sounds like fun for the royals and their staff to celebrate together, it was likely rather small in comparison to their most popular soiree - the Ghillies Ball.

Thought to have been a favourite tradition of the late Queen, and a custom that dated back to when Queen Victoria and Prince Albert would throw a summer party for their staff, the Ghillies Ball would take place in the summer during their long stay at Balmoral.

Designed as an event when staff could let loose with the Royal Family, the annual dance featured in an episode of Netflix's The Crown.