Despite moving house 24 times in 34 years, Norfolk has always been home for Lady Philippa Dannatt of Keswick, the new High Sheriff of Norfolk.

As an army wife, married to the man who eventually became the head of the British Army, she has lived across Germany and the UK, but home was always on the banks of the River Yare, just outside Norwich.

She and Richard, now General Richard Dannatt, Baron Dannatt, moved into their rambling riverbank home when they married, straight out of university. It looked across river, woodland and grazing marshes and was surrounded by land farmed by her father. As a child Philippa played here, and picnicked in the fields at harvest. As an adult it became a haven from the constant moves and worries of army life.

She grew up in Keswick and nearby Bracon Ash, the eldest of four sisters and part of the Gurney family whose Norfolk history stretches back generations. And it was here she and Richard returned year after year with their growing family. As well as their own four children, they took in a niece and nephew after the death of Richard’s sister, and eventually the house on the banks of the Yare became a focal point for their eight grandsons and great nephews too (with two more on the way).

By the time she met Richard, while studying for a theology degree at Durham University, he had spent several years in the Army and already won the Military Cross for gallantry. Shortly after they married he was posted to Berlin but, aged just 26, suffered a devastating stroke. Paralysed down one side, and unable to speak, he hung between life and death for 10 days.

“I remember thinking, ‘If he dies, I have absolutely nothing of him at all’,” says Lady Dannatt. She vowed that if he recovered they should start a family.

When Richard finally retired from the Army, having reached its very highest post, he took charge of the Norfolk farm. He was also appointed Constable of the Tower of London, which means that the couple have a home within the Tower of London itself. This astonishing house, weighted with the history of the nation, was where Anne Boleyn stayed the night before her marriage and then for the 10 days before her execution. Thomas More’s cell is just off the hall. “It’s the most extraordinary privilege and a wonderful place to be,” says Lady Dannatt.

It is a blessed existence but Lady Dannatt’s Gurney inheritance is not just wealth and land, but also a mission to put privilege to good use. It seems to run as powerfully and steadily as the River Yare flows through their land.

“The church and our faith have been a constant,” says the descendant of some of England’s greatest Quaker social activists. Indeed her husband considered a career in the church or politics, and Lady Dannatt spent much of her adult life longing for him to leave the army. She admits to “worrying terribly” about his safety.

In Northern Ireland they had to check for bombs under the car before every journey. She told her young son they were checking for hedgehogs until he informed her that his friend’s family next door looked for bombs under their car, which was so much more exciting.

During those four decades of service Lord and Lady Dannatt have raised huge sums for military charities. Lady Dannatt was made an MBE for her part in raising £5m in just nine months to provide places for the families of military casualties to stay while their loved ones were treated in hospital. Today their eldest son, Tom, devotes much of his time, energy and salary to looking after street children in Liberia and Sierra Leone – where the cathedral in Freetown has a monument to the Gurney ancestor who helped end the British slave trade.

As High Sheriff of Norfolk, Lady Dannatt’s theme for the year is mental health. She wants to encourage people to talk about mental health problems, so that they are not guilty secrets but illnesses which can be treated. As a young army wife and mother in Germany she was asked to train as a counsellor for Relate. She worked with families on the army bases and realised that many of the people she was seeing were struggling with mental health problems.

She knows a little of the pain herself: “I think it’s right that I say this – when three of my children were born I suffered from post-natal depression and it wasn’t discovered at all until the second one. It wasn’t on a scale that was in any way comparable to things other people go through, but it was enough to mean that I never want to go there again.

“People will tell you about their angina, and their migraine and any other part of their body, I just want to get people talking about their mental health too. For young men under 30 the biggest cause of death is suicide. Young men find it very hard to talk about their feelings. And if one was involved in preventing just one young man from taking his life it would be a huge achievement.”

Lady Dannatt is also keen to promote the work of Norfolk’s volunteers and small charities.

“I’m absolutely bowled over and very humbled by the number of people involved in voluntary work and I’m loving meeting them,” she says, adding: “I despair at the cuts. It’s impacting hugely on many of our charities.”

Lady Dannatt says it was her husband who was first approached to become High Sheriff, but he already had a lot of commitments around the centenary of the First World War. “I was delighted when they asked Richard and then surprised and delighted when they said that I was on the list in my own right,” she says.

Her father and grandfather were both High Sheriffs of Norfolk and her mother is thrilled that she is carrying on a family tradition – even if the historic regalia is not always appreciated.

“I went somewhere in King’s Lynn and they thought I was part of the dancing troupe! The dancers were very good, so I don’t think I would have added anything!”

Any spare time is devoted to her dogs, grandchildren and gardening. One of the dogs is called Delia, in honour of Norwich City Football Club, another family passion.

“I love Norfolk with a passion,” she says. “It’s always the big skies, and I love hearing the Norfolk accent. I love Horsey and the marshes, I love Cromer and Northrepps. We have a very large extended family so everywhere I go there are cousins.”

With Norfolk at the heart of her family for generations, Lady Dannatt says she is honoured to be able to spend a year representing the heart, and mind, of the county.