I fight the urge to turn on my heel when I get to Horn Please. It’s not just the look of the front door (“distressed”, and not in a good way), the litter on the steps, or the sign that reads “No spitting. Please use ashtray”. There’s the smell, redolent of the cloying fake scent emitted by mosquito coils; the joinery, if you can even call it that, which is as makeshift as you’d get on a building site; the elephant grey floor with its smelly painted surface that must surely be emitting volatile organic compounds; the use of Indian newspapers instead of wallpaper; the zinc pail that passes for a sink in the lavatory. Horn Please feels as poor as a food shanty in India, minus the exotic warmth and charm.

I’m obviously meant be amused by this improvised ingenuity. Someone here has a sense of humour. “We guarantee fast service however long it takes” is stencilled on the basement wall outside. There’s a list of house rules inside: “No scavenging cutlery. No sleeping in the toilet”. But I’m not feeling it. Instead I warn my guest that this could be one of the very worst meals we’ll ever eat. If this is the front of house, what does the kitchen look like?

But I’m wrong, big time. It takes a moment to compute that the “fermented rice batter, chickpeas” is actually a plateful of dhokla, the Gujarati savoury cake. A savoury sub-continental riposte to lemon drizzle cake, the lactic acid ferments in the batter thrill the palate as does a faint bonfire night smokiness. Its “tempered” (oil fried) aromatic topping of fragrant curry leaves, cumin, white and black mustard seed, and fresh green chilli look beautiful, and sends further pleasurable shockwaves to the olfactory system. Lentil and rice croquettes constitute another appetite awakener. Their mealy, spiced innards a hybrid that’s a bit like falafels, a bit like kachoris.

Despite my worst misgivings, the crab cakes are amazing, an addictive yellow mix of turmeric-bright potato, onion, and oil-popped mustard seed where the crab brings a subtle background fishiness. I finally eat my words about the kitchen with the accompanying crab salad, which turns out to be a knock out: a thin natural Marie Rose-style sauce, stippled with spice, coats the patently fresh white crustacean meat.

Delicate pastries stuffed with paneer and spinach sit on a butternut squash purée rescued from nondescript toothsomeness by its distinctive whiff of smoked paprika. When the lamb rack appears, I’m beginning to wonder if, counterintuitive though it may seem given the decor, there’s a chef in the kitchen from a fine dining background. Our rosy lamb rack, presented on a mellow tomato and coconut sauce, is the acme of tenderness. Its blackened spice crust holds our interest in its own right. Its cap of crisply fried, amber-hued grated potatoes is utter perfection.

One dish particularly intrigues me: gram flour yogurt curry with fried rice and crunchy masala okra. It’s served in a beaten-up aluminium wok-shaped receptacle, two dry, crunchy pakoras that seem fried to order perched on a dais of rice upon a creamy yellow sauce, all this strewn with longitudinal shreds of deep-fried okra. And I keep coming back to it because the assembly of flavours and textures fascinates me, above all the sharp, silky yogurt sauce, which juxtaposes so brilliantly with the fried elements. Even a potato paratha, oily and blistered from its contact with the tawa (griddle), leaves others that bear that name in the shade.

Desserts showcase intelligent fusion. Grilled peaches come with a reduced milk and sugar “rabdi” into which white chocolate has been introduced, alongside a cardamom-infused pannacotta. We spoon a warm dark chocolate dip as soothing as a silk pillow into roasted rice “sand” spiced with fennel, or dunk white chocolate and crispy corn “rocks” into it.

There’s just no let-up in the originality and risktaking, yet the kitchen pulls it off with aplomb. One chef is Spanish, the other Indian. Their collaboration is a triumphant two-fingered salute to those fools and fearmongers who would willingly choke off the flow of chefs from Europe and further afield.