The current vogue for casual dining, typified by sharing plates, small bites and communal tables, belies a new eating-out trend that is quite literally taking place behind closed doors: the rise and rise of the private dining room.

Restaurants that already have one are reporting unprecedented demand, and those who don't are creating them as fast as you can sear a pan-fried fillet.

This appears to be a logical development of the private dining at home phase, where chef would cook a high-end meal in his customers' own kitchens for a price. Cooking for private parties on his own stove with his own pans to his own menu is way less fraught with risk. And it's not to be confused with the Chef's Table, where diners sit in the kitchen in full view to watch the action as it unfolds. The very essence of this latest craze is absolute privacy.

Chef patrons tell me they are compelled to splash out on a private facility by sheer strength of market forces. Mark Greenaway, who opened the new 16-cover Balvenie Room at his fine-dining Edinburgh restaurant last week, told me he'd missed out on at least three big bookings over the festive period because he didn't have a private room; Tom Kitchin, whose Michelin starred restaurant in Leith re-opens on Thursday with a generous private room as part of a £1m expansion, also cites the popularity of the room at his sister restaurant Castle Terrace as one reason for creating it. High-end customers now expect it.

Such rooms are swathed in luxurious fittings. Bespoke sound systems where diners can play in their own tracklists, special lighting, limited edition crockery, handmade wallpapers, carpets, heavy curtains and lavish drinks displays are just the beginning. Bespoke menus and wine lists, and a small team of dedicated waiting staff, can also be part of the offer. So private diners feel they're getting special attention away from the prying eyes of the public and their pesky smart phone cameras. Most restaurants don't charge extra for hire; presumably the rewards must more than compensate.

This is of course good news for the hoi-polloi at table in the public restaurant area. Who, after all, hasn't experienced the frustration of having their cosy tete-a-tete conversation drowned out by the rising cacophony from the nearby table for 10? Hen nights are undoubtedly the worst. I recently had an entire meal out ruined by the presence of a group of 14 extremely loud women, some of whom actually wheeled their baby buggies past our table for the duration; management hadn't warned us beforehand.

Eating with friends or colleagues in a private room means you get to say what you like without the tut-tuts of neighbouring tables. Nobody else can hear your confidential insider business chat, family gossip or drunken indiscretions. Business deals can be struck, presentations made, arguments settled, friendships forged and photos posted over fabulous food and wine without disturbing others. It's all a far cry from the joyful chaos of the artisan burger bar.

And here's the thing. When asked what was the best thing about private dining, one un-named foodie's unhesitating response was: "Nobody else can see you and your friends spending obscene amounts of money." Clearly, a win-win all round.