Ratatouille. We eat it. We love it. So what could possibly go wrong with a single dish of stewed vegetables?

A lot, it turns out. Earlier this year, one of London's most esteemed restaurant critics filed a less-than-favourable assessment of chef Tom Sellers' latest joint Restaurant Ours. After the review in question – courtesy of Fay Maschler – any wild hype surrounding Sellers' otherwise promising second restaurant was dealt a shot right to the jugular. Her biggest snub? A dish of oh-so delicately arranged ratatouille that, auspiciously, was passed down to Sellers from the great American chef Thomas Keller.

"There is none of the unctuousness, the south of France-iness of real ratatouille," Maschler wrote in her Evening Standard review in June this year. "It is a dish for Instagram, not the mouth."

South Kensington's next big thing was reduced to a sobering failure in the space of 800 words. But there was more. Sellers retorted with a review of his own. A review of Maschler's review. The sarky response, however clumsy (he does cook, not write, after all), suggested they were words from the heart of a wounded artist.

Of course, Twitter lapped it up. Public commotion reinforced an opinion all critics share – that the bad reviews get the most interest. Just ask the Observer critic Jay Rayner – he wrote a book about it.

And, whether they do or not is pretty much exactly the point, as Rayner alluded to in an interview with Eater: "I'm selling newspapers and not restaurants. What really matters is the quality of my copy. If my copy becomes boring, unentertaining, and is no longer delivering an interesting account of the restaurants, I will be sacked."

I'm selling newspapers, not restaurants. What really matters is the quality of the copy

One thing critics don't agree on, however, is the extent of the power they wield to slap a new restaurant back up on the property listings overnight. "I still say, if the product is great, the people's view will win out," Tania Ballantine, Time Out's food and drink editor, tells me. "Interestingly, when I visited [Restaurant Ours] a few days after Fay's review, it still appeared full, at least on the ground floor. So it couldn't have hurt that much." Rayner echoes the sentiment in his book My Dining Hell. "We might be able to help restaurants along, but bad restaurants fail all by themselves."

Still, the dramatic demise of Le Chabanais last year could suggest otherwise. Marred by 'a gas leak' and a host of other alleged technical issues, the Mayfair restaurant didn't exactly help itself achieve the grand opening expected of it, not least when its world-famous Parisian sister restaurant – Le Chateaubriand – was looking on apprehensively from over the Channel.

In her review, Maschler wrote that the food was "bland" and "overpriced", and that the task of having to chase down the food on her plate was a "pointless game of hide and seek".

The joint was named after a Parisian brothel and Rayner's review confirmed, a couple of weeks after Maschler's, that it was indeed "a place where customers come to get screwed." The restaurant closed permanently about a month later.

But swings and roundabouts, as they say. The Guardian's Marina O'Loughlin (don't tell the others, but she's my favourite) gets the odd report of her reviews' effects: "I have heard about phones ringing off the hook. Of course, after the initial burst of attention, it's down to the restaurants to keep the momentum going by simply being excellent. I know of one chef with a burgeoning empire who has emailed to tell me that his success was kick-started by my review. I love this."

Ballantine has similar experiences of her reviews' effects: "I unintentionally met the owner of Patty & Bun a couple of weeks ago, and he told me the review was a game-changer for him [she gave the James Street joint five stars]. Whether that's true or was just the cocktails talking, I couldn't say."

Both Ballantine and O'Loughlin possess an advantage that the Rayners, Maschlers, Grace Dents, and Giles Corens of this world don't. And that advantage, figuratively speaking, is not having a face. Anonymity means a restaurant's service has nowhere to hide – not even under the tablecloths – and critics get the same experience as their readers.

"I've done it both ways and you definitely get a more realistic experience being anonymous," says Ballantine. "If you're recognisable, you get the good table. Me, I sit by the loos. Often. And I'm forgotten about. Often. The cooking isn't different, though how they handle a complaint differs vastly."

O'Loughlin, not being the sort to relish champagne showers and arse-kissing, prefers to keep it that way. "A high-profile chef approached my table in an East End restaurant saying 'You're Marina, aren't you?' but weirdly said it to my pal.

"There is an idea of what I look like in the ether – so a lot of 25-year-old Nancy Dell'Olio lookalikes out there probably get a lot more attention than they should."

If they write a bad review, it hurts like hell. But we have to take it on the chin

That said, Maschler thinks a bit of familiarity can salvage at least some positives from a visit, bad or good. "After doing the job since 1972 – 44 years and counting – I am almost invariably recognised. However, Quentin Crewe [Maschler's predecessor] used to say to people asking him for restaurant recommendations 'Go where you are known best'. It's not bad advice. Being greeted warmly is for most people a big plus in their evaluation of a meal out."

Also a big plus is no unwanted surprises. During his 40-year career, and with a restaurant empire to show for it, Chris Galvin has met a fair number of critics, it'd be fair to say. It'd also be fair to say many of them have been valuable informers of his success.

"No doubt in my mind that without them we would not have such well-advised guests," he tells me. "Giles Coren's review of Bistrot de Luxe sent it into warp factor eight! But I should say that a good critic will only communicate what they find on a visit."

More recently, Shoreditch's Santo Remedio – which only hard-launched a few months back – is seeing, for the first time, what a positive review can do. "When we first opened, our customers were locals who became regulars," says co-owner Edson Diaz-Fuentes. "We were busy, but not packed." That was before Dent, Coren, and Tom Parker-Bowles had something to say about it. "We now often have a queue. I think when people see a critic has recommended a place," he says, "it makes them prepared to wait."

As for Galvin, critics more often than not say good things of his six London restaurants. But a chef's cooking can be so personal to him that the bad reviews aren't easy to swallow. "If they write a bad review, it would hurt like hell. But we simply would have to take it on the chin, learn from it if it is accurate, and rectify the issues."

The London dining scene is forever being influenced, and you could almost call the critics the architects to its evolution – trowel in one hand, sledgehammer in the other. I ask Maschler how significant eating out is to shaping the capital. "London is a huge maw," she says. "What is getting digested at this moment could not be more important."