Now it’s sensitive William’s turn to be his brave wife’s strength and stay

Shortly before her death, Diana, Princess of Wales, confided in me about her two sons. She was particularly concerned for Prince William, explaining he took everything to heart, was suspicious of people’s motives and easily hurt.

‘William is the sensitive one,’ she said. ‘But I am sure he will deal with his problems. He will have to.’

The Princess added: ‘Being the intellectual one, he finds it harder. But he is very aware of people and their feelings – which will be to his advantage.’

Those characteristics of fortitude and empathy have never been more in need than they are now.

Having lived through the appalling experience of seeing his mother die so young and his father stricken by cancer barely a year after ascending the throne, the 41-year-old now has to summon strength and resolve to support his wife.

It was widely noticed that Kate praised his support in the video she released on Friday – in which to many people’s surprise, he did not appear by her side.

Being alone in front of the camera, Kate had space to take a degree of control while suffering from an illness that, she must feel, is trying to wrest its own control of her and her body

It is an insight into the tenderness and understanding William shows his wife, alongside whom, in private at least, he has long felt able to free himself from the burden of his birthright and the responsibilities and difficulties that imposed.

Indeed, that freedom forms the backbone of their relationship.

While they were friends to begin with, from the moment William met the then Kate Middleton at St Andrews University in September 2001, she bought him something that had been severely lacking in his life – normality and stability.

Their marriage cemented those qualities and he was determined to protect her. In fact, right from the start, it was her protecting him. Who can forget how, on their wedding day, she was the one offering supportive words as they travelled from Westminster Abbey to Buckingham Palace by carriage.

‘Are you happy?’ she whispered. William also has a set of wonderful allies, and in particular Kate’s mother Carole.

The Middleton women pride themselves on being strong and throughout this difficult year Carole has been there for him, reassuring and caring.

She, in turn, has been impressed by her son-in-law’s care for her daughter: even before Kate’s cancer was known about, she marvelled to friends at how supportive William was.

The women in his life have proved significant in other ways. From his paternal grandmother, and even great-grandmother, William has learned the importance of putting on a brave face in public, just as he has done in recent weeks.

Diana told me it was never something he was comfortable with but duty came first – a mantra painfully adhered to when walking behind his mother’s coffin at her funeral at the age of just 15.

He hadn’t wanted to do it and he hated every moment but he was persuaded by his grandfather, Prince Philip, that if he didn’t, he might regret it for the rest of his life.

Much has changed since those devastating days, not in the least William’s relationship with his brother Harry, a bond once soldered over the candlelight of shared grief.

Since his brother has abruptly created a new life away from his family, the importance of Kate, as William’s ‘strength and stay’ (to borrow his grandmother’s epithet for the Duke of Edinburgh), cannot be understated.

For now though, it is his turn to be strong and focus on making as smooth a path as possible for Kate’s recovery.

It’s yet another trial in which I have no doubt he will succeed.