'It takes traditional Loire-ish notes as jumping-off points, and gives them a bravura, 21st-century, Brit flourish'
We're in a long, rowdy room, squeezed round a tiny, marble-topped table and rammed so close to other diners we could be inhaling their boozy breath. Opposite us, a chap decants fatty rillettes from a jar and mashes them on to plates with a scattering of cornichons. The place is heaving with cheery, swilling punters, and staff are harassed and dismissive in a "Désolé– you're not on my station" kind of way. Remarkably, we're not in Paris.
This is tourist-infested Covent Garden, a former boozer plonked among the leisure-clad hordes on their way to The Mousetrap. It has been artfully gutted, only the name – Green Man & French Horn– remains, a piece of serendipity for its new owners, the chaps behind bistro raves Terroirs, Brawn and Soif. It accidentally hints at the new USP: "Food and wine from around the longest wild river in France. From the Ardèche to the Coast at Saint-Nazaire." That's the Loire, that is.
Some of France's more familiar wines come from this area – saumur, muscadet, sancerre – but the vast list here also stars far more recherche grapes: romorantin, grolleau gris, menu pineau. Plus, the company's speciality – wines described as "natural" or "biodynamic". People far cleverer about wine than I am can tell you all about these, but one is made without chemical, technological or biological intervention, the other is dictated by the moods and tides of Gaia, and growers strip naked to howl and dance in their vineyards under the full moon. Or maybe that's druids.
Anyway, boy does it polarise opinion: adherents foamingly evangelical, detractors equally rabid. I've sympathy with both. I've necked cloudy sauvignon so luscious that I returned to 40 Maltby Street the next day to buy a crate of it, but also a barbera of evil murkiness that tasted like the fag-end-steeped dregs of a students' party. However, there's nothing we order here that I don't like. I've dragged along a friend who's obsessed with the stuff, and we order by the glass – a Saumur Bulles de Roches ("Zappy, bright, more frivolous than champagne," says the friend); a natural vouvray ("Lean, full of flavour, like a bite of a perfect apple"); and Domaine de la Chevalerie from Bourgeuil ("Semi-natural, beautifully structured cabernet franc").
It's easy to get carried away with a list the size of an erotic novel and with, for me, a far more tingly effect, but the food is just as titillating. It takes traditional Loire-ish notes as jumping-off points – freshwater fish, seafood, lots of pork and game, tarte tatin – and gives them a bravura, 21st-century Brit flourish.
So, white onion soup, rich and sweet with a base of remarkably good stock, is topped with crisp, oily croutons and seasonal salers cheese. There are slender leeks, braised into silkiness, scattered with egg yolk mimosa and little brown shrimps. A flawless slab of wild turbot (and so it should be at £26) comes in a lake of beurre blanc as soothing and lush as a warm spring day in the Loire Valley.
All those wines by the glass leave us with a bill as dizzying as the booze. But it can be done on a shoestring. We also have the plat du jour – fat, velvety chicken livers with fried egg and artichokes, served with a glass of creditable house red, for a tenner.
Detail is impressive: the baguette is first-rate sourdough; the beurre blanc is laced with excellent wine (der, obviously) and the aromatic whisper of shallot. Ingredients are carefully chosen and frequently rare – freshwater zander, coucou de Rennes chicken, potatoes from Noirmoutier (as expensive as they're exquisite).
Green Man & French Horn doesn't pretend to be a destination restaurant; the food isn't astonishing or groundbreaking, it's just good. But if you were drowning in theatreland flotsam and fell upon it, it would feel like a vine-covered lifebelt. I wouldn't be surprised if it were still here in 20 years: it has all the makings of a minor classic.
• Green Man & French Horn, 54 St Martin's Lane, London WC2, 020-7836 2645. Open Mon-Sat, noon-11pm. Meal for two with drinks and service, £90-plus.
Food 7/10
Atmosphere 7/10
Value for money 7/10
Follow Marina on Twitter.