The Duchess of Cambridge, who is celebrating her 40th birthday, has emerged as Britain’s reliable royal.

After Prince Harry and Meghan’s stormy departure to California in 2020, the death of Prince Philip last year, and now sex abuse allegations against Prince Andrew, the former Kate Middleton remains the royal family’s unsullied trump card.

In the public eye she is the ever-smiling mother of three who can comfort grieving parents at a children’s hospice or wow the nation by playing piano during a televised Christmas concert.

“This is the woman who was the commoner who married into the royal family and who has not tripped up, not caused any embarrassment,” observed Katie Nicholl, author of Kate: The Future Queen.

“It’s not been an easy year, and yet somehow Kate seems to be a bit of a beacon in all of this.”

At a moment when the House of Windsor is facing more than its share of controversy, Prince William’s spouse has won accolades for her commitment to early education, art and music.

The charities she supports gush about her willingness to get personally involved in their causes.

Olivia Marks-Woldman was touched by the care Kate put into photographing Holocaust survivors Steven Frank and Yvonne Bernstein for an exhibition sponsored by the Holocaust Memorial Day Trust.

Before the shoot, the duchess spent time learning her subjects’ stories and used that background knowledge to compose the photos, said Marks-Woldman, the trust’s CEO.

“It was a really involved, thoughtful participation,” she recalled.

“But even after those photographs had been taken, the duchess supported the project and supported Steven and Yvonne and took an interest in them and sent them Christmas cards, invited them to the carol service in Westminster Abbey recently and has just been wonderful.”

Tracy Rennie, deputy chief executive of East Anglia’s Children’s Hospices, has a similar account from the day Kate visited one of the organisation’s facilities in 2019.

The duchess agreed to talk with the parents and other relatives of a child who had recently died because they wanted to meet her, even though their pain was still raw.

“It was a really supportive conversation actually, to the point we were having a laugh and a joke together as a family before we left — you wouldn’t imagine that in such a difficult situation,” Rennie said.

“They absolutely felt honoured that she’d taken the time out and were overwhelmed by the fact that she was a ‘normal person’ — their words, not mine. They felt she really cared.”

The daughter of a flight attendant and a flight dispatcher, Catherine Elizabeth Middleton was born in Reading, England, on January 9, 1982.

-AAP