‘You know what I’m going to ask you to do, don’t you?’

Ron sighs.

‘Ring it in, I suppose.’

‘It would make my life a hell of a lot easier.’

‘Do you want me to supply her full address?’

‘It would save time if you did. And time is of the essence.’

‘The things I do for you.’

‘It’s not for me, Ron, except in the way of saving my job. It’s for Liam, and Evan, and for whoever might be next.’

‘OK, I’ll do it. But I’ll be driving to a secret location and using an untraceable phone.’

‘You’ve got a burn phone?’

‘Haven’t you?’

‘Ron Perdue,’ says Naylor, finally getting her slot to cross the roundabout, ‘there’s a lot more to you than meets the eye.’

‘I sincerely hope so,’ says Ron.

In the incident room, they’re studying a satellite view of Sunderland. The most prominent feature by far is the river, an undulating muddy snake until it reaches the dockside and the surprising blue of the sea.

Hagen uses a mouse to focus on the double bridge carrying both traffic and the railway lines. With the bends in the river, the good news is there’s a relatively short stretch of the banks from where you’d see the bridges. And on those banks, there are very few buildings where there are flats with river views.

‘Looks like here or here,’ says Naylor. ‘University halls of residence, or this building here, the Echo building. It was supposed to be Sunderland’s best address when it was built, but by all accounts it’s a bit ropey these days.’

‘I don’t think it’s likely to be the halls of residence,’ says Hagen. ‘Too much turnover and in the hands surely of the university admissions office.’

‘I agree,’ says Naylor. ‘The only problem is, the Echo building’s huge. There must be over a hundred flats in there. We have to find a way to narrow it down.’

The situation seems ridiculous, but also fun. Naylor assumes a serious expression, and speed-dials a number on her phone. Across the office, she hears Dallabrida’s absurd but funny ringtone – a tannoy announcement, Will the man with the twelve-inch penis please pick up your phone? – and watches him discreetly as he pulls the phone from his pocket and glances at the screen. When he sees who’s calling, he turns his back to her.

‘Hey, beautiful,’ he says.

‘Hey, handsome,’ says Naylor. ‘How’s tricks?’

‘I’m doing OK. Just thinking about grabbing lunch.’

‘Lucky you. Me and Hagen have bagged ourselves a ride out to Woking.’

‘Is this your way of telling me you’re breaking our date for this evening?’

‘Not breaking it so much as letting you know there’s a possibility I might be late.’

‘How late?’

‘You should know better than to ask anyone who works in this office a question like that.’