Istanbul has wonderful nightlife, although Erdogan’s agenda may soon end much of that. I’ve been there four times and been showered with famous Turkish hospitality. My oldest and best friend there is a senior professor who, last time I was there in 2014, was running a conference at which I was speaking. There was always going to be a great dinner sometime that week. But this one would be unforgettable.

She invited her best friends at the conference to a restaurant about 400 metres from the conference centre in the Taksim district. It was in a quite narrow, newish high rise building of about 10 floors, cheek-by-jowl between other similar anodyne structures. We caught the lift from street level up several floors. There were ten of us: several locals, a French woman, me and my wife Trish, and others I can’t remember. There were three men among the ten. I landed at a part of the table with great conversationalists.

There was feverish talk about the mess Turkey was in. All the Turks at the table were incendiary about the creeping erosion of the secular state under Erodgan. Angry accounts were given about daughters having to wear headscarfs for university entrance interviews or be instantly rejected. About jailed journalists and academics and the small-mindedness of those in power. The women were feisty feminists with commanding jobs in a male dominated culture. They all drank alcohol and bossed the waiters around.

About an hour into the meal, the restaurant was full and people were loose and enjoying themselves. The two women opposite me suddenly said emphatically “Oh. My. God.” They were staring past our side of the table and looking through the restaurant windows into the building next door.

There, not five metres away, was a room with the lights on. A gossamer thin white curtain had been drawn, but with the lights on inside, we could see everything in the room. The curtain presumably prevented them from looking out clearly. A very overweight middle aged naked man and a considerably younger, large breasted and full-bodied woman, also naked, had entered the room, perhaps from the bathroom. They set about their tasks. The quick consensus was that she was a prostitute he had called out to his hotel. If we were wrong about this, the man was punching well above his weight if this was his wife or girlfriend.

Our table had the box seat for the spectacle, but there was no hiding what they were up to from almost every vantage point in our restaurant. Very quickly those on other tables got up, brought their drinks with them and crowded round behind our table to get the next best view. Young couples, small dinner groups, a few elderly couples and the staff all joined the throng.

Every new phase of the performance drew gales of laughter. When she took him in her mouth, some cheered and roared. “It’s a wonder she can locate it under all the fat!” “Ah, the first course is now being taken”. When the missionary position changed to rear entry and we saw the man’s thin little bottom gamely pounding away below his considerable back, there were lots of eewws and “oh my gods!” and goodness knows what else being said in Turkish.

This was the first time I had ever watched live sex in a room full of mostly strangers. Or actually, in any context.

I had these thoughts.

First, I’m confident that, presented with a questionnaire on what we would do in such a hypothetical context, nearly everyone in our group would have not hesitated to affirm that, of course, they would have asked for the restaurant curtain to be drawn, or dispatched a waiter into the next building to tell the occupants to please turn off their lights. But presented as we were with the opportunity to watch proceedings – unknown to the performers – no one could look away. The asymmetry of consent between the watching and the watched just flipped the ethical compass for everyone. “They don’t know they’re being watched. We don’t know who they are. We’ll never see them again, What’s the harm?” would have run the rationalisations.

Far more than that, everyone just roared at the spectacle. Far from there being any awkwardness, everyone instantly decided this was spectacular luck we’d chanced on. No one seemed to spend a nanosecond surreptitiously checking non-verbally with others how they should behave. It was uncontrollable, communal, bawdy unity that had been instantly let off its leash.

I wondered too about whether the reaction of the room would have been any different had the performers in our hotel window theatre looked very different. What if we had decided that they were two young honeymooners, with the bridal gown draped over a chair? Or a sweet, long-married couple from the Turkish countryside, in town for a short holiday having saved up for months? Or elderly tourists, lovingly pleasuring each other in the privacy of a hotel room during a holiday? What if the man had been lithe, muscular and handsome instead of fat and out of shape? What if their ages had been similar? Would any of this have changed our response?

It struck me that the essence of the hilarity went something like this: hiring a prostitute is a private and generally clandestine, knowingly shame worthy activity, nearly always done by men with the power to hire women to do something that many people routinely experience as a mutually exchanged gift from someone with love and affection for them. It’s something the man would have probably been hugely embarrassed about, had he known of the audience. Embarrassed about his cover being blown and about his less than film-star like body. So the laughter here was about the combination of the shattering of the man’s hopes to keep his private vices private and the sort of mirth occasionally experienced when we experience or see the wind or a wardrobe malfunction expose body parts in an everyday situation.

His innocent misjudgement about the lighting had transformed him from a man with the power and means to buy sex to an unwitting public cuckold, providing entertainment to a roomful of diners.

Most of our only experiences of watching others having sex is via filmed pornography, occasionally almost unavoidable to anyone using a computer. There, unless the acts are filmed and uploaded without the consent of those involved, the performances are consumed as inauthentic and clearly commercial: they are doing-it-for-money, or purposefully, consensually exhibitionist, in the case of amateur uploaded porn. But here we witnessed a couple in action who were quite unaware that their private, transacted intimacy in fact had an audience.

So public virtues, as might be expressed in a serious-minded conversation about respect for privacy, the ethics of the right thing to do in everyday life or of the case for prostitution took a running jump against the power of private vices – here, the temptation of force-fed voyeurism, of a box-seat on what goes behind closed doors.

I’ve told the story dozens of times, and have even had friends say “I hear that you had an amazing dinner in Istanbul once”, wanting to hear the details for themselves. It seems there’s a little voyeur in most of us.