Queen Elizabeth worried that it would be difficult to organise her funeral if she died at Balmoral, Princess Anne has revealed.

But she was persuaded by her family that she should do what felt right, according to a documentary charting King Charles’s first year as monarch, to be shown on BBC One on Boxing Day.

Featuring unseen behind-the-scenes footage and exclusive interviews with key officials, family and senior royals, it captures the galloping pace of the last 12 months.

In a moving segment, Anne talks about her mother’s death and how she felt when she saw the Imperial State Crown taken off the Queen’s coffin for the last time at St George’s Chapel at Windsor. ‘I rather weirdly felt a sense of relief – that’s it, finished,’ she said. ‘That responsibility being moved on.’

The Princess Royal, who remained exceptionally close to the late Queen throughout her life, also said: ‘I think there was a moment when she felt that it would be more difficult if she died at Balmoral.

Queen Elizabeth worried that it would be difficult to organise her funeral if she died at Balmoral, Princess Anne has revealed

Princess Anne talks about her mother’s death and how she felt when she saw the Imperial State Crown taken off the Queen’s coffin for the last time at St George’s Chapel at Windsor

‘I think we did try to persuade her that shouldn’t be part of the decision-making process.’

Many considered it fitting that the Queen died at Balmoral because she had such a deep love for the Scottish Highlands.

Shortly before her death in September last year, she was visited by Dr Iain Greenshields, the moderator of the general assembly of the Church of Scotland, who said afterwards that she spoke of how it ‘gave her a great deal of peace and pleasure to be at Balmoral’.

The Princess Royal revealed that it was ‘pure serendipity’ that she was by the monarch’s side when she died. She explained that she had only stopped over at Balmoral Castle on her way back down south after spending a few days on Scotland’s West Coast.

Anne also gives her sister-in-law Camilla the royal seal of approval and says the support she has given her husband the King is ‘outstanding’.

King Charles seen in incredible behind-the-scenes Coronation video

Many considered it fitting that the Queen died at Balmoral (pictured) because she had such a deep love for the Scottish Highlands

The Royal Banner of Scotland above Balmoral Castle flies at half mast following the Queen’s death

Members of the Royal Family, King Charles, the Princess Royal, the Duke of York, the Earl of Wessex, the Prince of Wales, the Duke of Sussex and Peter Phillips

The Princess Royal said: ‘I’ve known her a long time off and on. Her understanding of the role and how much difference it makes to the King has been absolutely outstanding,’ she says.

‘This role is not something that she’d be a natural for but she does it really well. She provides that change of speed and tone, that’s equally important.’

Anne told the documentary that, despite a lifetime waiting in the wings, it was difficult for her brother to prepare himself completely for the moment he acceded to the throne. The documentary was written and co-produced for Oxford Films by the Mail’s own royal expert, Robert Hardman.

■ Charles III: The Coronation Year will be shown on Tuesday, December 26, on BBC One at 6.50pm.