Alan Mayhew’s house is a mid-terrace which stands out from its neighbours for its lack of improvements: no double-glazed front door, no skylight in the attic, no window boxes or fake stone cladding. When Hagen knocks, a neighbour answers, throwing open her own door as if she’s the one he wants.

‘He’s not in, duck!’ She’s heavy-set, a bruiser, her brash Nottinghamshire accent as thick as slurry. ‘He’ll not be back while three.’

‘Where is he, then?’ asks Hagen, and she points to the end of the street.

‘The White Hart, duck,’ she says. ‘Every day, twelve while three.’

The pub’s what the Lamb and Lion used to be before the brewery’s gentrification: sticky bottle-green carpets, ugly brown tables and chairs, an indifferent landlord reading a newspaper behind the bar. Hagen pays a quick visit to the cold and draughty toilets, where there’s no hot water on the basins and the hand-dryer is broken.

In the tap-room Mayhew’s easy to pick out, drinking alone at a corner table holding four brown bottles and a glass. He’s trimmed his beard since the booking photo was taken, but even in the gloom, Hagen sees his health has deteriorated, his skin tinted yellow with encroaching jaundice. His head sags, and his eyelids are fluttering in a half-doze.

As Hagen approaches the bar, the landlord folds his paper and rises from his stool.

‘Now then, youth,’ he says. ‘What can I get you?’

‘Nothing for me, thanks,’ says Hagen. ‘I was hoping for a word with Mr Mayhew.’

He nods to where Mayhew is sitting.

‘Which are you, then, bailiffs or coppers?’ asks the landlord. ‘Not that it matters. Whichever you are, you’re two hours too late. If you want to get any sense out of him, come back tomorrow.’

‘Is he drunk?’

‘He’s one of those drinkers who’s never quite drunk, but he’s close enough to it. Four barley wines’ll do that to a man. You ever tried a barley wine?’

‘I don’t think so, no,’ says Hagen.

‘If you’ve never had a barley wine, be grateful. My grandad used to reckon it was the best stuff you could use for getting a good shine on brass and I’ve never had reason to doubt it. And see there all the good it’s done old Alan. His liver’s shot but he’s a creature of habit, four bottles a day, come hell or high water, with a whisky chaser or two if he’s feeling flush. He says he drinks for the pain, but we could all say that in Mansfield.’

‘He’s in here every day?’