They walked back upstairs to inspect bedrooms complete with dusty four-poster beds, and bathrooms with ancient plumbing and stained ceramic baths. The roof must be leaking in places, because some of the ornate plasterwork on the ceilings was crumbling and in danger of collapse. Cooper found it sad to see history mouldering away. He’d rather a hotel or conference centre moved in and restored the place, installing en-suite bathrooms and a fitness centre.

Many armies had marched across Derbyshire over the centuries, and not just in the Civil War. It struck Cooper that Alder Hall would have been newly built when Bonnie Prince Charlie led his Jacobite rebels south as far as Derby in the winter of 1745. Wasn’t it the Duke of Devonshire’s regiment, the Derby Blues, who abandoned the city ahead of the advancing Highlanders? But instead of pressing on to London and overthrowing King George II, the Young Pretender had begun the retreat to Scotland. A major turning point in history had happened right there.

Cooper wondered whether the Saxtons had been Jacobites in those days, or loyal to the king. Catholics or Protestants, Royalists or Parliamentarians. There were times when everyone was expected to take sides.

In one of the bedrooms, he heard the sound of an engine, and looked out of the window. Down below, a small blue car was turning in the driveway, making a slow three-point manoeuvre that barely caused a crunch of gravel. From two storeys up, he could make out that the driver was a woman in a short skirt. He could see her legs, and one arm on the steering wheel, but that was all. He wasn’t even sure of the make of the car – a lot of those compact models looked the same. And he was at the wrong angle to get a view of the number plate. The vehicle had moved out of sight to Cooper’s left before he could glimpse a single letter.

‘Will you want to inspect the grounds?’ asked Casey, without much hope of escaping just yet.

‘We’d like to see the woods near the eastern boundary.’

‘Ah, yes. Well, in that case, we could visit Fair Flora.’

She stood on a pedestal in a high clearing, deep among rhododendrons. She’d been named after the Roman goddess of flowers, and she held a garland in her left hand, clutched across her breast.

‘The statue is said to have originated at Chatsworth House,’ said Casey. ‘But she was given to the owner of Alder Hall a long time ago by one of the dukes.’

‘It’s a strange place to stick a present from the Duke,’ said Cooper. ‘Shouldn’t she be in the house?’

‘She was originally. But the arrival of Fair Flora coincided with a period of ill fortune for the family at Alder Hall. Hauntings, too, they say. Anyway, they decided Flora was to blame, so she was banished to the woodlands.’