Days start early at Highclere Castle when we transform it into Downton Abbey. My husband, Geordie, rises first to let in the cast and crew who turn it into the seat of Lord Grantham. Geordie is much better at getting up than I am, but I can still hear him curse as he's speared by a sharp Palm Court-style potted plant when he opens the shutters by the front door. The set design team and Charlie from props lead the charge into the castle. Lighting balloons start going up into the air, video village comes alive with the trolleys, computers and headphones proliferating.
Our labradors look out for the crew's back- packs and often strike lucky with some sand- wiches. Since it's our second year of standing in for Downton, we know the gravel drives around Highclere Castle will turn into a white van convention. Small white vans, white lorries and white articulated trucks, food trucks, make-up trucks, costume trucks and 80 or 90 crew cars park up. Thick black ropes of cabling start to snake through the rooms, windows and doors of the castle, often blocking them open.
If the temperature drops, the 90-odd members of the crew don thick sweaters over the unspoken uniform of black jeans, dark tops and trainers. Then they pull on windcheaters (black, of course), which they wear inside the castle as well. They become walking eiderdown coats and ask us how we can live in the castle, because it is so cold. So much equipment dominates all the floor space that it's a wonder the castle looks quite so beautiful through the camera lens.
Into all of this arrive chauffeur-driven cars bearing Maggie Smith, Hugh Bonneville, Brendan Coyle or Jim Carter. The actresses carefully hurry in the front door, those for "upstairs" in beautiful changes of clothes, while those from "downstairs" bring their imagination but not the wardrobe.
The castle's script involves no words, but John Gundill, the castle manager, and I carefully read through the notes for each block of filming in advance, highlighting our concerns as necessary. We've filled filing cabinets with comments on behalf of the castle. It has a definite character and like all character actors, there are occasional contretemps, which are leavened by laughter when the castle refuses to compromise on a point of potential breakage!
It's a majestic building that soars across the Hampshire countryside, and a building has occupied the same ground for over 1,300 years. The Carnarvon family have lived here since 1679. This last creation was the dream of the Third Earl of Carnarvon who had the castle refashioned and rebuilt by Sir Charles Barry, the pre-eminent Victorian architect who was building the Houses of Parliament in London at the same time.
While it has 200 or 300 rooms, it remains a family home and we love to live in it and share it with our friends. Downton's creator Julian Fellowes and his wife Emma have often stayed with us and know it well. Julian is passionate about the castle. His understanding of how the building works, of the spaces across which the family and staff move, is a bedrock in the series.
Despite being full of beautiful works of art, including paintings by Van Dyke and ancient Egyptian artefacts brought back to Highclere by the Fifth Earl from his archaeological digs in the 1920s, the house is not a museum. It's full of the family and people who work here and the ghosts of those who have worked here in the past. They're now all delightfully muddled up with the Downton Abbey family - both upstairs and downstairs.
We took a staff photograph during the summer of all the key people who live or work with us. The list numbered 80, although many of them work part-time. They also have to multi-task in a way that Downton's Carson would find quite unacceptable, not only looking after our family but catering for commer-cial events too.
But Carson would recognise the sense of community. A hundred years ago there would have been up to 60 full-time members of staff living in the castle, with many more living in cottages in local villages. In fact, Lord Carnarvon felt he was responsible for as many as 250 families at the outbreak of war in 1914.
The story of Highclere Castle during the First World War has real parallels with the television series. The Countess of Carnarvon of the time was called Almina, and she was an extraordinary lady. Just like her fictional counterpart Cora Crawley, the Countess of Grantham, she persuaded her husband to turn the castle into a hospital, filling it with nurses, a doctor, installing an operating theatre, and welcoming the exhausted, bloodstained soldiers who arrived day and night to her home.
She brought down the best specialists from London, and became an expert nurse, saving men's lives and limbs, offering succour to their families. She always wanted to hear of the progress of her patients after they had left Highclere to convalesce, often by the sea. So many of these men then returned to the war, but they never forgot her, her untiring generosity and cheerfulness, and those that survived corresponded with her for years.
Generals and doctors who worked with Lady Almina during the war wrote letters paying tribute to her efforts, calling her a modern Florence Nightingale. Recently I sat down to incorporate the stories I found in these letters into a book I was writing about her and the "real Downton". It was emotionally testing. How could I do them justice? It was then quite surreal to walk out into the Downton Abbey cast dressed in their First World War fatigues, bringing to life this extraordinary chapter in the castle's history.
As the war drew to its close, the real story of Highclere and its residents couldn't be more exciting. Lady Almina's husband, George Edward Stanhope Molyneux Herbert, Fifth Earl of Carnarvon (the great-grandfather of my husband, George Reginald Oliver Molyneux Herbert, Eighth Earl of Carnarvon), was an enthusiastic Egyptologist who'd received a concession to dig in the Valley of the Kings.
In 1922, together with archaeologist Howard Carter, he discovered the tomb of Tutankhamun, but died in Cairo a year later. He was buried on a hillside overlooking Highclere. Lady Almina went on to marry Lt Col Ian Dennistoun, and died in 1969 at the grand age of 93.
Downton Abbey may be a costume drama but it's one that's set in a world peole can relate to as cars, planes, telephones and even electric light begin to be present in everyday lives. The characters are facing decisions about careers and lifestyle, love and divorce, still relevant today.
It is no surprise that viewers have become wrapped up in the intriguing twists and turns of Julian Fellowes' brilliant plot and fallen in love with members of the cast both "upstairs" and "downstairs". But I could not be prouder that the central and largest character by far is our beautiful home, Highclere Castle, built and maintained with such love and care, and expressing such optimism and hope.