Laura leaned forward. ‘You told me that once you went to your father’s grave while you were asleep and begged him for forgiveness. Do you think that what’s disturbing you might be something to do with your father? Something that happened when you were a child maybe, that’s now rising to the surface again?’

‘No,’ Shields said brusquely. ‘He was a good father and I tried to be a good son. It’s nothing to do with him, I assure you.’

He’s lying again, thought Laura.

‘You said you’d see if there was somewhere that could take me in, Dr Archer. Because I think the time has come, for everyone’s safety, including my own.’ He pointed to the dressing. ‘To make sure I’m somewhere secure at night.’

Laura nodded. ‘Yes, Mr Shields. I’ve spoken to a sleep clinic, but I’m afraid it’s private. To get you seen under the NHS will take much longer. It’s a purpose-built facility for monitoring sleep in a controlled lab. It’s not intended for long-term stays. Most people only sleep there once, to be tested, but as your case is extreme, they have agreed to do a series of tests on you over several consecutive nights. My hope is that they will pinpoint something medical, rather than a mental health issue.’

‘I’ll pay. I can’t go on like this. I’ll find the money. Where is this place?’ He looked at her eagerly. ‘Can I go tonight?’

‘Fenchester, and, yes, if you want, I can ring them and tell them you’ll be with them this evening.’ Laura didn’t like the strange fervour in his eyes, but she was relieved to be free of his sudden desperate visits for a couple of days.

‘I was rather hoping that I’d be going to a secure hospital of some kind.’ Shields gave a short cheerless laugh. ‘Listen to me — normal people never ask to be locked away, do they? But I’m afraid for my sanity, doctors, I really am.’

‘The clinic is the place to start, Mr Shields,’ said Sam. ‘As Dr Archer says, let’s rule out a medical cause, but I do urge you to look at your childhood, and try to think of some trauma that you might have suppressed. I’m certain it’s something from your past that’s at the root of your distress.’

Laura noticed the look of irritation that flitted across Shields’s face. If he kept blocking it out like this, she’d never be able to help him. ‘Have you managed to talk to your mother yet?’ she said. ‘Speaking to her might help identify whatever it is you’re repressing. She could be the very person to throw some light on it.’

‘She’s an old lady. I can’t lay this on her. Sorry, Dr Archer, but I won’t do it.’