The REAL mistress of Downton! Highclere Castle's Lady Carnarvon on how the TV show saved her beloved home It was no accident that the magnificent Victorian Highclere Castle was chosen as the setting for Julian Fellowes" all-conquering TV drama, Downton Abbey. The eighth Countess of Carnarvon and Julian's wife, Lady Emma Kitchener-Fellowes - Lord Kitchener was her great-granduncle - had long been friends. Fiona Carnarvon and her husband George (known as Geordie, the eighth Earl) wouldn't want to over-state their input into Downton's storylines. But when Julian and Emma are here and we're sitting around the dining room table chatting, I know that some of what Geordie and I may be sharing will somehow surface on television. Julian is a writer, and writers are sponges, aren't they. In fact, the connection goes back many years. After he'd written Gosford Park, he tried to get it filmed here in 2001. I was disappointed when the director, Robert Altman, chose to set the movie elsewhere - but not any more. Highclere Castle's Lady Carnarvon on speaks about how the TV show saved her beloved home - and confronting the ghostly footman who haunts it And with good reason. Pre-Downton, Highclere, on the Hampshire/Berkshire border, attracted around 100 coach parties a year. Since the first series was screened in the autumn of 2010, that number has increased six-fold. So the impact on the castle's coffers is almost incalculable, the huge uplift coming at a time when the 5,000-acre estate was battling debts running into millions. Lady Carnarvon is full of easy smiles and unforced charm, although there's little doubt that you're in the presence of the chatelaine of Highclere. She is Geordie's second wife, and met him two years after his first marriage broke down. He has two older children, a daughter Saoirse, 22, and 20-year-old George (Lord Porchester), who will inherit the estate, and then a 13-year-old son, Edward, from his marriage to Fiona. Does she empathise with Downton's Cora, played by Elizabeth McGovern, a "commoner" who married into the Crawley family and became Lady Grantham? She deflects the question. "I think I might have tumbled to her duplicitous lady's maid, O'Brien, a little quicker," she says. But Cora sees the best in everyone. I've learned that it's never a good idea to have too intense a relationship with a member of staff because it can skew your relationships with everyone else. The estate's relationship with Downton began after Lord Fellowes and producer Gareth Neame decided to revisit Gosford country with a series set in a stately home. "He always had Highclere in mind," says Lady C, "because he told me so." The Earl and Countess thought carefully about whether to let ITV's production crew film in Highclere's interior. What concerned us most at that stage was that we were about to get into bed with a company and we weren't quite sure how they were going to portray the house we love. It's Geordie's family home. I wanted him to be comfortable with how it was brought to the screen. The clincher was the Carnarvons" relationship with the Fellowes. They gave us the confidence to take the gamble. With so many people clattering around the house, Lady Carnarvon, 49, hasn't spotted any of its famous ghosts in a while- pictured with husband George But they had little idea of how successful that gamble would be. We've worked hard but we've also been lucky. The first season was the most relaxed because we didn't know what we'd created. I remember saying to Julian, "Do you think anyone's going to watch this?"" Of course, Downton proved to be the most successful UK period drama since Brideshead Revisited three decades earlier. Throughout the four series that have been filmed so far - the latest of which will air in the autumn - either Lady Carnarvon or the castle manager, John Gundill, has been present on set. The answer, I think, is to approach everything with a fair degree of humour. Mind you, when I first saw big lighting poles being carried into the dining room and missing the priceless Van Dyck portrait of Charles I by an inch, my heart was slightly in my mouth. No food or drink is allowed in the house. But that's the rule if filming is taking place in any National Trust building or stately home. If you've got a crew of 90 people and they all leave mugs of tea behind the pillars, it would be a disaster. What the viewer sees on screen is a mixture of family possessions and items imported by the production company. The library is ours, as are all 5,600-plus books. There's wire in front of each shelf so no books can be taken out. The tasselled lampshades are theirs. The sofa and footstool belong to us but the cushions are imported because my cushions cost quite a lot and I didn't want them ruined. I try to educate cast and crew that they can't put their bottom on a certain chair, for instance, because it was Napoleon's and it's too frail now. The second series, apparently, was more fraught than the first. It took place during the First World War, which meant a succession of military beds and paraphernalia appearing each day at the house. I had to be sure that there were rubber protectors on the legs of each bed so they wouldn't mark the floors. With so many people clattering around the house, Lady Carnarvon, 49, hasn't spotted any of its famous ghosts in a while. I did once see the ghost of a footman who seemed unhappy. So when Geordie and I took over, I had the house blessed by a monk called Father Peter from Westminster Abbey. He blessed the dining room where we'd be eating and some bedrooms. And then he blessed the spot where I'd seen the ghost to wish him on his way. I'm not convinced he's gone, though. When Shirley MacLaine turned up to film her scenes as Cora's mother Martha Levinson in series three, Fiona showed her around Highclere's exhibition of Tutankhamun artefacts - the fifth Earl, a keen Egyptologist, and Howard Carter discovered his tomb in 1922 - and she picked up on the vibes too. She really enjoyed it, she told us, but then she explained she'd been an Egyptian in one of her many former lives. The BBC and ITV don't pay huge location fees so the couple are looking to capitalise in other ways by writing a book Presumably, the Carnarvons receive a substantial sum for allowing Downton to be filmed there? "No," she says. The BBC and ITV don't pay huge location fees. It's why we're always looking to capitalise on the success of the TV series in other ways. I wrote a book, for instance, about my predecessor, Lady Almina. Now I've written a second, Lady Catherine And The Real Downton Abbey, covering the years from 1922 up to the end of the Second World War. Of course, any money we do earn is ploughed back into the house. If I'd wanted endless pairs of Manolo Blahnik shoes, I married the wrong man. It's more important to Geordie, as it is to me, to spend that money on mending a carpet or replacing lampshades. I replaced 80 in my first year alone. Everything here is held in trust - but then we think of ourselves not as the owners but as the stewards of Highclere. Hugh Bonneville as Lord Grantham uttered a similar line in the first series of Downton. I think Geordie must have said it enough times at supper, which is where Julian will have heard it, I'm sure. Lady Catherine And The Real Downton Abbey is published by Hodder & Stoughton at £20 on 12 September.