‘Eventually, though you wouldn’t be very popular asking them to look. There are screening procedures that take ages if you haven’t anything to go on. If you asked them specifically to look for phosdrin it would probably only take a morning to get the results back.’

‘I see,’ George said, giving nothing away. ‘ Yes. Thank you. You have been remarkably helpful.’

She would have gone on to tell him about her latest claimed rarity, but George disentangled himself from the conversation and replaced the receiver.

His next call was to another friend, a retired detective superintendent who had worked for most of his career in Carlisle. George asked as tactfully as he could whom he should contact at Appleworth Police Station to be sure of receiving a sympathetic and intelligent hearing.

‘Come on, George!’ the man said. ‘Spit it out! You want to know which of them has more brain cells than the average chimpanzee.’

‘Not exactly,’ George said. ‘It’s a delicate matter. I wouldn’t want the Appleworth officers to think that I’m trying to teach them their job, but I’ve had access to certain information that they’d not come across otherwise.’

‘Benwell,’ the man said. ‘ Dave Benwell. He’s a young detective inspector. He’s not flashy. Not one of those that has to show off in front of the men. But he’s confident enough of his own ability not to resent being offered help. He’s a grafter, too. Stubborn, once he gets his teeth into a case. Behind the scenes. You know the sort.’

‘Where would I get in touch with him this afternoon?’

‘I’ll give him a ring if you like,’ the Superintendent said. ‘Put in a word for you. Find out if he’s free. Important, is it?’

‘Oh yes,’ George said. ‘Very important.’ He paused and spoke almost to himself: ‘ I think it’s a case of murder.’

When he finished his phone calls he went back to the kitchen where Molly was sitting by the Aga, waiting for him. She was reading a favourite John Le Carré spy novel but could not concentrate and when he came into the room she set it aside.

‘What’s going on?’ she said. ‘What is this about?’ She was angry. They had been married for all these years and they were in this business together, yet still he felt he had to exclude her. She thought he was making a fool of himself, skulking in the scullery, shutting himself in the living room with the phone.

‘I’m sorry,’ he said. ‘I know it seems absurd, but I’m not convinced that Ursula died of natural causes.’

‘Why?’ she said.

‘It was too sudden,’ he said. ‘I know she was in her seventies but she was as strong as an ox. Besides, there are other facts that don’t tie up.’