Not much has changed in the labyrinth of corridors beyond it, aside from the lilac uniforms the housekeeping team are bustling past in. They were blue in my day.

As we turn the corner to where a bank of monitors used to be tucked into a cubby under the stairs, I’m reminded of Ian, the security guard who worked here at the same time as me. He was Canadian and we forged a friendship over the fact that neither of us had visited the other’s country, even though we were neighbours.

I’d spent many a lunch hour hunched under these stairs, eating a limp sandwich whilst alternating between studying for my licensing exams and playing the ‘business or pleasure?’ game with the guests. Ian and I would bet on whether a couple were here for work or play, going by their body language and how they greeted one another. It never ceased to amaze me how often a furtive peck on the cheek in the lobby was a prelude to them taking it in turns to ascend to a room on the upper floors. Ian would almost always win the wager, but then he’d seen more secret liaisons than I’d had hot dinners. I can’t help but wonder how much he would have put on Jacob and me the other night.

‘Do you know the date?’ asks Andy, his fingers poised over the keyboard.

‘June twenty-first,’ I say.

‘And approximate time?’

I wish I could pinpoint the moment I’d left and Jacob was still there, but I can’t even remember when I got here.

‘It would have been around 9.30 p.m.,’ I say.

Andy sits down and inputs the date and time into the system, which doesn’t look too dissimilar to the one Ian used to operate. He clicks the mouse, turning the lobby into a time-lapse video, sending guests scurrying in and out of the shot. As the timer in the corner approaches 21.27 he clicks again and the recording returns to real time.

‘OK, so why don’t we take a look at the entrance first,’ he says. ‘See what time he left, if indeed he did.’ I can’t help but wince at his foreboding words. ‘You said he was supposed to check in?’

I nod. ‘But I called reception the following day and they had no record of him.’ It’s only as I say it out loud that it occurs to me I was asking for the wrong man. ‘Actually . . .’ I muse. ‘Could you check again for me, under another name?’

Andy nods and pulls a notebook out of the top pocket of his suit jacket.

‘Can you try Michael Talbot?’ I say.

‘I’ll go and check now,’ he says. ‘Are you OK to stay here for a minute? I’ll leave this running, so you can keep an eye on it.’