Turnips is an haute cuisine restaurant inside a greengrocer in Borough Market in London. I suspect others will try this conceit soon — it is the sort of dishonest fantasy affluent anti-vax mothers enjoy as they peddle their oblivious self-hatred on smartphones made of minerals hewn by child slaves — but not like this. Turnips is indisputably magical. Perhaps I say this because it is almost completely outdoors but still warm. These are mad times, even for mad times.

Borough is a good place to feel the throb of the ancient city; but particularly now. It has the toughness and ennui of a district that says: global pandemic, kids? What else you got? Look at late-capitalist masculine inadequacy disguised as a skyscraper called the Shard. What else you got? Look at the replica of the Golden Hinde, the pinnacle of 16th-century luxe yachting and still it had Rattus rattus. What else you got? Look at Laurence Fox forming a political movement from the ashes of Lewis and Whatever Love Means: What else you got? I then imagine Borough burping in contempt and wiping its mouth. It isn’t quite as comforting as eating by the sign in Weymouth that says ‘Bubonic plague was here’ (I paraphrase). But almost.

Turnips is in a vast cavern under a railway arch painted white and held up by gaudy green poles: it is cosy, various and brightly lit. It has a thrown-together kitchen; tables among pumpkins that seem to glint; stores on vast shelves overhead. It looks like a field hospital for root vegetables that cooked haute cuisine by mistake, or despite itself, or through some mad enchantment summoned by despair. It is the antithesis of the wealth aesthetic that painted every-thing first beige and then — as if beige was too mercurial — grey. In the ordinary restaurants of the rich nothing happens. That is what you pay for: the absence of life. The food is incidental. In a market anything can happen. I think we used to be more interesting. We might be again.

In late spring Turnips the green-grocer, which has been in Borough for more than 30 years serving the restaurant industry, heard its friends at the City Social — a fine and diffident joint — were unemployed and invited them to set up in the shop. And why not? It’s a variant of the let’s-put-on-a-show-kids film that made MGM so much money in the Great Depression: a fable about the transformative power of imagination and love.

‘Tasting menu’ is usually a phrase that sends me moaning for Valium because you are sold art but more often digest vanity. Not here: there is something incredible about Turnips, something rare. Its honesty, with that thrown-together kitchen, its skill — the chef is Tomas Lidakevicius — and its joy create the best meal I have had since 2016, when news accelerated and everything went wrong. Or maybe it just feels that way. It doesn’t matter.

We eat a glorious mushroom and cep dumpling with wasabi under a wild green foam, as pretty as it is tasty, and more surprising for existing in a market; an exquisite piece of bream under flowers with a basil oil; a pear crumble with white chocolate, which melts into itself; a strawberry cheesecake that shames New York with its delicacy and power.

I watch Lidakevicius cook in his field kitchen with something like awe. This is a restaurant for survivors, and it’s £65 a head without wine. It deserves to be so fashionable it is ruined, and it will be.