Standing on the stairs, greeting guests who have arrived for a tour, I often begin with a guessing game, which is good fun audience participation. How long has Highclere been a home? How many rooms are there or how many showers? A few willing guests take a guess and, often getting it wrong, it acts as an excellent ice breaker. If it was a TV show of course, they could ring a friend or ask the audience or otherwise simply Google the answer.

In the winter the most pressing question may well be how is the Castle heated. Originally, of course, it was with fires and all the bedrooms, including the house staff ones, still have fireplaces. Some of the fireplaces are marble, carefully chosen, carved and with detail which I too often walk by. Even as far as the second floor, the mantelpieces are rather beautiful. There is a dumb waiter which was used to help the footmen haul the coal and firewood up to the nursery floors and above.

With candles and flame, the risk of a fire required careful, watchful observation and, in our case, in the past, a night watchman would patrol the corridors. Fire escapes were clearly signposted and there were, and are the remains of, fire chutes on the top floor. I do know people here who actually had to practice in them 60 years ago. They acted as a canvas slide, wedged in a window at the top, and held in place by men who you hoped were your friends at the bottom, thus ensuring a safe inclined angle, rather like a bouncy slide. I am not sure I would like to try one although I have always wished I could exit the Castle via a helter-skelter. Running back upstairs to have another go would be good exercise and keep me warm.

Today, fireplaces remain in use in just the major State Rooms and there are now two large boilers in the cellars, fed from an enormous oil tank outside. There are some radiators on the ground floor and a few on the gallery but no radiators in the bedrooms. A couple of days before guests arrive we shut all the shutters and curtains and open the bedroom doors to encourage heat to go in and stay there, although we also switch on the white panel radiators which I bought for each bedroom. Not necessarily beautiful but most welcome. The next level of heating is hot water bottles, and beyond that, an extra sweater and socks will do the trick. I like having the windows open anyway and on holidays as children in Cornwall, the windows leaked air which came in gusts off the sea.

John, our inestimable Castle manager, comes from Yorkshire and the windows in his office are usually open, there are no radiators, and he merely wears a thicker sweater and a fleece jacket. One might think it might lead to shorter meetings but sadly not. In contrast, the office team next door believe in hats, blankets and scarves. Their window is closed, the curtains tucked around to keep out the drafts and they do have a radiator.

Rather typically for an English estate, the dogs and horses are well looked after and, in the course of renovation of the courtyard block, there are now radiators along an outside stable wall and a lovely one in the tack room, thus making it a very good place for meetings.

Overall, I suspect the temperature in the Castle has not changed hugely over the years, which ensures a stable atmosphere for the works of art whether they be furniture or paintings. We all walk quite a lot in the course of a day. Sometimes John claims he has done his 10,000 steps by 11am, which I am not sure I believe, whilst my husband is busy taking a walk because he has a watch which tells him his heartbeat is going up every few minutes so he has to go for a walk to calm down.

Today, there is no night watchman but a high level of smoke alarms and fire detectors throughout the Castle, as well as constant, diligent care regards all wiring. Having checked inside each evening, John walks briskly round the outside, keeping warm by looking for errant slivers of light from shutters and thus completing his step count for the day.