‘You don’t need to come along,’ he said to Fry.

She shrugged. ‘What else would I do?’

Cooper thought of mentioning that she was supposed to be moving to a new flat this weekend, but it might not be the right subject to raise when he’d abandoned her so suddenly last night.

They drove down into the landscaped parkland that occupied the fertile valley of the River Dove and extended well up into the lower slopes of the hills on either side. For several minutes they seemed to be passing along a perimeter wall around the estate. Dense plantations of trees covered much of the landscape.

‘Are there wild animals in these woods?’ asked Fry.

‘Bound to be.’

‘There’ll be badgers, I suppose?’

‘What?’

‘Badgers. They spread TB.’

Cooper shook his head. ‘Only to cattle, Diane. You’re perfectly safe.’

Badgers were a difficult subject at Bridge End Farm. Matt was likely to explode if anyone mentioned them as being cute, cuddly animals. Unlike the situation in other parts of the country, Derbyshire County Council had banned a badger cull in the county, despite incidents of TB being reported among local cattle. So it was quite likely that somewhere on the Knowle Abbey estate, the badgers would be below ground, waiting for the night.

Further on the abbey itself came into view. From this angle it seemed to be an almost random collection of porticos, balconies, windows and castellated extensions. Its size was impressive, but its architectural design would never have won any awards.

Villiers called Cooper back just as he was driving through the ornate front gates of the abbey.

‘Hi, Carol.’

‘Yes, Ben, you were right. Nothing too serious, but there have been some reports of threats and vandalism. An intruder reported one day in the grounds, that sort of thing.’

‘Threats? Against who?’

‘General abuse, most of it. Though the earl’s name was mentioned, of course. They had some obscene graffiti. There was even an anonymous letter, which is a rather old-fashioned way of doing it. Most people like to write their threats and abuse on Twitter or Facebook these days.’

‘Most young people,’ said Cooper.

‘That’s a point. But wouldn’t you think—’

‘What?’

‘Well, the average middle-aged Derbyshire resident doesn’t resort to writing threats and abuse to people they don’t know.’

‘I suppose it depends whether they have a reason,’ said Cooper.

He followed direction signs to the estate office. Just inside the park they passed a walled topiary garden, with hedges clipped into the shape of an eagle’s head. The Manby family emblem.

The estate offices at Knowle Abbey were housed in part of the old coach house block, next door to the restaurant and craft centre. They were met by a young woman with short red hair and a brisk manner. She was wearing a navy-blue body warmer with her name on a badge. Meredith Burns described herself as an assistant estate manager.

‘Thank you for coming along. You must know about our unfortunate incidents,’ she said.

‘I’m sure your neighbourhood policing team has been to speak to you,’ said Cooper.

‘Yes, they have. But we didn’t expect too much to come from it, to be honest. Not a visit from a detective sergeant anyway.’ She looked at Diane Fry. ‘Or two, in fact?’

‘Yes,’ said Fry.

‘How unusual.’

Cooper could sense an instant animosity developing between Fry and Meredith Burns. It was something that seemed to happen when Diane Fry was involved. She must give off some specific pheromone that he couldn’t detect.

‘I believe you received an anonymous letter,’ said Cooper.

‘Yes, about three weeks ago. We didn’t really think anything of it, until the vandalism.’

‘Oh, yes. Can you show us?’

‘This way.’

Meredith Burns led the way along a gravel path that headed away from the stable block along the east wing of the abbey itself.

‘Apart from a few medieval stone carvings, the only remnant of the abbey’s early history is the former Chapter House, which is now the Manby family’s private chapel,’ she said.

When they turned a corner of the abbey, it was immediately obvious that the arched front of the chapel was suffering from the ravages of time, along with the effects of weather and pollution. Meredith Burns explained that it had been placed on the Buildings at Risk Register ten years previously. Specialist conservation work had been started, but the money ran out. Now lots more cash was needed to save it from complete destruction.

‘We estimate that the necessary work will take around eight years to complete, at a cost of over a million pounds,’ she said. ‘Our immediate priorities are to prevent water penetrating the core of the building and damaging the delicate carvings and statues. Obviously, we also need to conserve and repair the eroded masonry. We’d like to examine the façade for any traces of medieval paintings, before they disappear completely. And the entrance steps to the west front will need repairs too.’

They were approaching the rear of the chapel, where a small mausoleum became visible in its shadow. Burns turned to Cooper.

‘We don’t have many years left to do these things, before some parts of the chapel get beyond repair,’ she said. ‘That’s why we’re seeking donations and sponsorship to help us rescue it. This is a national treasure.’

‘Sponsorship?’

‘We’re trying to get grant aid from the English Heritage Lottery Fund. But there’s a lot of demand for grants and it wouldn’t cover the total cost of conservation anyway. We’re asking visitors to make cash donations for the appeal via donation boxes inside the house and café. We’ve approached several local and national companies to become sponsors of the campaign. But times are hard for everyone.’

A sheet of blue plastic had been secured over the back wall of the chapel, as if repair work was under way. But when Burns lifted a corner of the sheet, they could see that it was concealing the graffiti that had been sprayed on the stone wall in red paint. It was clearly something you wouldn’t want your paying visitors to see.

‘Why is it that people who spray graffiti never know how to spell “Fascists”?’ commented Fry.

Burns dropped the plastic back into place. ‘They always know how to spell that other word, though,’ she said.

‘And the letter?’

‘Come through into the office for a few minutes,’ said Burns.

Inside the abbey every room had huge Georgian sash windows with wooden shutters. Here in the east wing, all the window frames were rotten. Cooper reckoned it wouldn’t take more than a few seconds with a jemmy to remove the panes of glass or wrench out the catch. What on earth did the insurance companies have to say about an arrangement like this?

In places there were bare floorboards and cracked plaster on the ceiling. The heads of various species of antelope and impala mounted on wooden plaques stared at each other from the walls.

One room they passed through was enormous, two storeys high, with furniture including a grand piano and a full-sized billiards table. A large fireplace was dominated by an almost life-sized family portrait and a couple of red sofas had been roped off to keep the public away. Cooper shook his head at the sight. Did the earl and his family sit here of an evening, gathered in this huge, draughty room that must be impossible to heat properly, perched uncomfortably on those ancient sofas, looked down on by mounted antelope heads, staring at the glass cases with their collections of stuffed animals?

‘There are bullet holes in the wall here,’ said Cooper when they reached the offices.

‘Friendly fire,’ said Burns.

‘What?’

‘There was a detachment of American soldiers billeted in this part of the abbey during the Second World War. I gather some of them were a bit trigger happy.’

‘It looks as though they used the impala for target practice.’