We heard flat-footed steps coming down a staircase and a voice yelling – ‘I’m coming, hold your fucking horses …’ And then the door opened.

He was tall, white, early twenties, unshaven, with a mop of brown hair and naked except for a pair of underpants. He was thin though not unhealthy. His ribs stuck out but he almost had a six-pack and his shoulders, arms and legs were muscled. He had a big mouth in a thin face that opened wide when he saw us.

‘Oi,’ he said. ‘Who the fuck are you supposed to be?’

We all showed him our warrant cards. He stared at them for a long second.

‘How about a five-minute head start to hide my stash?’ he said finally.

We surged forward as one.

The ground floor had obviously been converted from a garage and then notionally split in two – faux rusticated kitchen area at the back, open-plan ‘reception’ at the front, with an open-sided staircase running up the left wall. Open-plan houses are all very well, but without a traditional hallway to act as a choke point it’s laughably easy for a trio of eager police to roll right over you and take control.

I got between him and the stairs, Guleed slipped past me and up the stairs to check there was nobody else in the house and Carey stood in front of the man deliberately placing himself just inside the guy’s personal space.

‘We’re family liaison officers,’ he said. ‘So in the normal course of events we’re not that bothered about your recreational drug use, but this attitude depends entirely on whether you give us your wholehearted cooperation.’

‘And provide coffee,’ I said.

‘You do have coffee?’ asked Carey.

‘We’ve got coffee,’ said the man.

‘Is it good coffee?’ shouted Guleed from somewhere upstairs.

‘It’s proper coffee. You make it in a cafetière and everything. It’s bare wicked stuff.’

‘What’s your name?’ asked Carey.

‘Zach,’ said the man. ‘Zachary Palmer.’

‘Is this your house?’

‘I live here but it belongs to my mate, my friend James Gallagher – he’s American. Actually it belongs to some company, but he gets the use of it and I live here with him.’

‘Are you in a relationship with Mr Gallagher?’ asked Carey. ‘Civil partnership, long-term committed … no?’

‘We’re just friends,’ said Zach.

‘In that case, Mr Palmer, I suggest we repair to the kitchen for coffee.’