As I booked a ticket for the most expensive meal I have ever eaten, it did ­occur to me that I don't like sushi. But this was not the only problem for someone who has been a lifelong ­feminist campaigner against the sexual exploitation of women: I was about to eat raw fish off a naked woman's body.

I first noticed the publicity for a monthly series of British "nyotaimori" evenings last summer. Nyotaimori, or body sushi, is Japanese, and it isn't normally on offer in London. But periodically temporary operations do pop up in cities around the world, each time sparking newspaper headlines. The word nyotaimori is usually translated as "female body presentation", but a friend who has studied Japanese tells me it means something more like "piling something on top". Which sounds significantly less appetising.

"Flash Sushi will offer a limited number of places to this unique ­experience," the advance publicity for these new British evenings said. "Places are extremely limited and demand is high. Guests will ONLY be informed of the location of the next Flash Sushi dinner once they have paid for their sitting in full."

What did the organisers expect to happen? Hordes of hungry sushi devotees turning up at the venue ­begging for a pair of chopsticks? No, they ­simply wanted to avoid the kind of scenes witnessed in Seattle in 2003 when a group of angry feminists waved placards and shouted as diners made their way in for a nyotaimori dinner.

Anyway, on Wednesday, this angry feminist arrived at the London address she had been sent after shelling out £250. I had to walk through a hippy cafe serving bean stew and carrot salad, and then finally – after going up and down a filthy fire escape and getting lost in a dark corridor smelling of cats – I pushed open a door and found myself in a dark room festooned with purple velvet and filled mostly with men in their 20s sipping champagne.

I was greeted by a Japanese woman in traditional dress and, down a steep set of stairs, caught a glimpse of the dining room. It was 7.05pm, dinner was due to begin in 25 minutes, but the naked women were already in situ, laid out as if in a morgue, ­awaiting a postmortem.

I stood out a little amid the assembled diners. There were two other women, but they were hanging on to the arms of their partners and were dressed to the nines. Soon, however, I was chatting to Ben, a money ­broker, recently divorced and in his 50s. He was at my table with two young ­bankers and their partners. The other table was all male, and, like everyone on my table, all white.

As we sat down, I realised the claims that "demand is high" for such dinners are rubbish: the trestle tables were easily long enough for 24, but there were only 12 diners. In fact, nyotaimori may take place in Japan, but it is stigmatised there and usually only found in seedy sex clubs. But wherever and whenever it is launched overseas, it is marketed as a form of Japanese food culture, and this was, ostensibly, what the meal on Wednesday night was about.

Our human plate was olive skinned, with (as far as I could gather) no body hair and naked except for a few strategically placed banana leaves and rose petals. Her eyes were shut. If it was not for the fact you could see her breathing – and the odd flutter of her eyelid – she could indeed have been a body in a ­mortuary. There was nothing remotely erotic about the sight.

The first course arrived, plus more champagne and sake. Soon the men were getting sloshed. I started to worry about their chopstick use, so much so that I ­offered to serve the salmon sashimi to the banker sitting furthest away from the plate. Loud guffaws from the other table, followed by clapping, came in response to one of the men dropping his piece of sushi on the woman's groin area.

Ben spent most of the evening ­telling me how nyotaimori is not ­demeaning to the women. "So long as they get paid," he argued, it is no different from being an artist's model. "In fact, it is art," he said, warming to his theme.

Our human platter did not look warm. I was dressed for the freezing cold weather outside and was slightly chilly. She had goose bumps, and it was not yet 8pm. The dinner was due to finish at 10.30pm. If it was torture for me being here, what was it like for the plate?

"What I like about her," said Ben, ­indicating our plate – who, playing dead a mere two feet from our mouths, could obviously hear every word we said – "is that ­occasionally she has a very slight smile on her face." I could only imagine that she was fantasising about sticking chopsticks in the eyes of each and every one of us.

At one point I moved my notebook and accidentally knocked the plate's ­fingers. She remained impassive. Andy, one of the bankers, told me a story he had heard the day before about ­nyotaimori. "Some geezer told me you can cop a feel of the birds, you know, slide your hand under the leaves when you are getting the food. So I called the organisers and asked if that goes on, and she tells me, 'No way. It is art.' So I knew it was OK to bring the missus."

Eventually, a break was announced in order for the "models", as our host referred to the human plates, to "stretch their legs". We were led upstairs. I asked how much the plates are paid. "I don't know," said the host. "We hire them through an agency." Do they have any special training? One often reads about how the plates involved in body sushi are "trained" to lie still for hours. "No, but we don't take women with large breasts as the food would slide off."

Were these events usually men-only? "Yes, but when there are ladies present it civilises the men." What ­happens when they are not being ­civilised? "Oh, nothing much, just boys' stuff."

Ben told the host how much he was enjoying himself. "And the presence of these ladies has totally legitimised it – I no longer feel like a dirty old man."

One of the men from the adjoining table approached Ben and the ­bankers. "Can we swap tables with you? Your model is gorgeous." But there was no need. As we were led back downstairs I saw that the plates had swapped already. Our new one had a ­tattoo on her upper arm facing me and her feet were bigger than the previous one's. Her eyes were closed and she too looked dead except for the breathing. I wondered what would happen if she got a terrible itch. More food ­arrived, this time hot, and the banker, in his haste, dropped a piece of hot cod on one thigh. "I wonder if, when she gets home, her husband says, 'Christ, woman, you stink of fish!'" said Ben.

I asked the women at my table what they thought of the evening. "Great," they chorused. "The food is lovely, the candles are beautiful and I love the atmosphere," said one. But what about the human plates? "I'd forgotten about them," she said, unconvincingly.

Not for the first time that evening, I wished I was outside in the freezing cold, shouting and waving a placard.

Names have been changed.