I am not really sure how they do it at Barrafina. I don’t mean the food: it almost goes without saying that you eat brilliant tapas. But how do they organise it?

The Drury Lane branch is tiny – except for a few outdoor tables in summer, eating is only at the bar with waiting and drinking around the edge. But it’s the other side of the bar that’s the spectacle. In a pub, three staff would be tripping over each other in a bigger bar. But on our most recent visit, there must have been a dozen people there prepping, filleting, changing the ice under the fish, roasting, grilling, frying, blanching, plating, dressing, washing up, pouring drinks and running front-of-house. It’s a feat of organisation and somehow it’s also utterly spotless. Everyone smiles and seems happy. In the heart of theatreland, there’s something theatrical about it.

Even if the food was less top notch, it would be worth paying to observe service in progress. But it is top notch. It also performs a great trick that not every tapas place manages: the plates can look meagre, if lovely, and after three you start to worry that you haven’t ordered enough. Then after the fifth you’re glad you weren’t tempted by the bread or the olives or the anchovies or the beef.

We haven’t been to Barrafina so often – maybe five or six times – but I have always been biased towards it because of the Hart brothers’ excellent Modern Spanish Cooking from the days when there was just the one restaurant, Fino on Charlotte Street. The book’s tortilla recipe is accompanied by a lovely picture, but try as I might, mine has never looked like the book. And it has certainly not looked like the version we had recently in the restaurant. It wobbled like a pannacotta when it was set down, it yielded to the lightest touch of the knife, and as it popped open out oozed glowing orange egg juices. It tasted as light as it looked.

Equally light were sobrasada croquetas, a special. Such was their fragility, a handle with care instruction would not have gone amiss, but then they delivered a powerful sweetly, spicy, salty kick of fluffy croquette.

The other stand-out dish was serranito. We got that order wrong, assuming it would be some cured ham (Serrano from a little pig? Little slices?). Oh no, it was a sandwich – apparently Andalucia’s answer to fast food and often served as a main after tapas, which is sort of how we had it. There were meltingly soft cubes of pork, cured meat and roasted pepper in the softest of rolls. When is a sandwich not a sandwich? We’ll remember that one for next time.

You could smell the cuttlefish empanada coming and the toothsome quality of the ink black cephalopod contrasted nicely with the flaky pastry. Anywhere else this would have been a fine dish; in Barrafina it seemed almost ordinary, which is a complement of sorts.

I didn’t enjoy the baby gem salad with manchego, pine nuts, pancetta and botarga as much as I had hoped. I craved some fresh greenness from the gems, but I found them overwhelmed by the smothering of salty manchego. That’s probably the point but it wasn’t quite what I wanted then.

Because we had time – unexpectedly, we had been seated without any wait – we finished with arroz de leche and cuajada, the latter with a little piece of honeycomb on the side, a nice detail. Both were very good.

It’s not cheap, Barrafina, particularly when you add wine, which, frankly, I feel is over-priced. We ate lower-priced options, avoiding the lobster, prawns and other pricier plates from the fish menu (unlike the Japanese group around us who seemed to take exactly the opposite attitude to the menu) but it still mounts up. It seems churlish to mention the price when the food is so remarkable, surely able to exceed the highest expectations in Madrid, Barcelona or San Sebastien, let alone London. Barrafina presents simple dishes extraordinarily well, with flair and little twists but (the gems apart) never detracting from the heart of the dish. Barrafina could easily become a habit, in our case pre-opera. We cannot afford that, but perhaps we can allow ourselves a more regular treat.

And it wasn’t only the food that meant we didn’t begrudge a penny. There was also the spectacle of seeing a football team’s worth of people working in an area smaller than a goal mouth, in perfect harmony and apparently with a real pleasure in what they were doing. Surely it cannot always be like that and perhaps it would be interesting to see it otherwise. For now, we’ll take marvelling at the way it all works.