Country & Garden: My family and other exhibits

Don't stare," Nanny used to hiss when we pressed our noses to the chickenwire nailed up to stop any child considering a three-storey dive from the nursery window into the rose garden. "It's rude!"

Search me as to why it was rude to look. They couldn't even see us, those Sunday visitors of 40 years ago who had been lured up the drive by the "House Open" sign. They'd done the house, seen the priest's hole, climbed the carved staircase, got their postcards and now, with a light drizzle causing their heads to droop, they were dutifully doing the garden tour while our parents counted the half-crowns beside the front door and asked themselves - again - whether 30 visitors in two days (six of them children at half-price) could be called, by any stretch of the imagination, a success?

Five years on, we were out of Nanny's care. House-opening was still a regular Sunday afternoon event in which all the family participated. My brother, aged 10, offered visitors rides on the lake at sixpence a crossing and, when the fancy took him, popped out of the priest's hole with a bloodcurdling yell. I took to the roof in my bedsheet and paraded up and down moaning like a banshee, in the hope of being taken for a ghost by the mackintoshed ladies admiring the borders.

"Up!" I willed them. "Not at the tulip tree - here! Woo-woo!"

A waste of clean linen and creative endeavour. No ghost story I've ever heard about the house - and I've heard plenty - mentions a parapet haunting.

We gave up weekend openings in the late Sixties after three Sundays in a row on which nobody turned up at all except a cyclist who said that the charge - it was a pound by then - was daylight robbery, and went away again. At least there was never any shortage of scones for tea after my mother had baked for the hundreds who failed to arrive.

In the Seventies, parties of 20 or more, by prior appointment, proved to be a more manageable approach, plus four days of opening for good causes (hospitals, Red Cross, National Garden Fund).

In the Eighties, the Canadians rode to the rescue with vast and jolly groups who paid to have dinner with the family and didn't grumble if they had to rub knees and elbows with their hosts because of the squash. It was a blue day for us when their tour group went bust.

This spring, a new light was thrown on opening a small but stately home. (It isn't, I should explain, a Chatsworth or a Longleat. The rooms you see are the rooms the family live in; there's no flat tucked away from sight, no hidden series of gilded apartments in which we loll among the caviare pots or wonder which field to flatten for the new pet-jet to glide down on.)

This was the year that we finally made it into the (rock bottom of the) big league, thanks to the heroic efforts of a man who's spent the last five years plotting how to make us into a tourist attraction. And we were! The view from the house, from Sunday morning to late Sunday night, was of Agincourt crossed with Alton Towers. The park, all white tents and Tannoys, was twanging with arrows from the laser archery ground (run by hugely muscular gentlemen dressed up as bow-toting foresters); the view beyond the garden was of a steely sea of car roofs. I put on my best silk dress and high heels to teeter across the grass at 10am and announce that we were open for business.

The sun shone. The crowds came. The portable lavatories worked. The tickets for tours round the house sold out. Nobody fell into the lake, twisted their ankle, or was felled by a stray arrow or thumped by a runaway shire horse. And on Tuesday morning, you'd never have known there'd been a thing in those fields beyond a flock of sheep and their wobbly-kneed offspring.

What we hadn't reckoned on - what would probably have kept away the friends we'd asked to stay the weekend - was the discovery that we ourselves were going to be among the sights, along with the clowns, the owls, the action- bike demonstrators and - a huge draw, this - the fire brigade with their how-you-don't-put-out-a-fire show. The room we had set aside for peace and quiet, the library, has three big windows looking out on the garden, at ground level. No barriers.

"Don't stare!" I'd have liked to see Nanny telling these visitors. Ten or 12 at a time, they pressed their faces to the glass. No smiles. No scowls. Just stares. Watching my mother go out of the room, my son pick up a book, a friend bend to tie his shoelace. Then perfectly ordinary actions suddenly felt as contrived as if we were on stage. My mother, finding no change in the bland expressions when she waved, smiled or, growing crosser, shrugged, thought she'd cracked it.

"They think we're holograms!" she wailed. "It's worse than if we were waxworks!" My son, trying to comfort her, offered the thought that this was what it must be like to be famous, to be robbed of any right to privacy, any belief that you could possibly need it. "They've paid," he said. "We're part of what they get."

Whether we were worth it is another question. Our private life had never seemed so dull as it did when thrust, for two long days, on to this highlit stage. Next time, if we don't put up a few restricting ropes, I think we'll go with the flow and play out a murder or a love match for the spectators. In the meantime, I'm forced to admit that I felt a weird sympathy for the birds of prey who formed part of the show in the park. Chained to their perches and ringed with warnings that they were to be observed but not touched, their role seemed as bizarre as ours - actors in a play without a plot.

Thrumpton Hall, Nottingham, is open by appointment throughout the year and on four Open Days each year. For details: 0115-983 0333

Duff Hart-Davis is away