On 12th May a new café opened in Covent Garden: in itself a not unusual episode, central London changing restaurant units with the same rapidity as we change socks - but what made it newsworthy was the way it announced itself to the world. Black Penny came without fanfare. It came without noise. It came, instead, over Instagram,

Even if very successful, Black Penny was by no means the first restaurant to control Instagram's extraordinary power on opening day. "We only invited followers on Instagram and Twitter," says John Cadieux, chef of the first Burger and Lobster on Clarges Street, "but by the time we opened it was like we'd been established for months." 

For the chef, stressed to get his restaurant off the ground in a congested market, such instant popularity is manna from heaven. "One follower is followed by another follower is followed by another who's Jay Rayner," Cadieux says simply. "It's a gold mine for our industry, where there isn't the money for marketing."

At the time of writing there are almost 150 million photos on Instagram hashtagged food (#foodporn shows up on just over 67 million images, while #foodie racks up 21 million). "Sharing" these days is more likely to mean posting a picture on Instagram and tweeting it than offering your mate a chip.

It's influencing our behavior, too: "there is that classic Instagram pause when guests at the table all take their photo, setting it up in the way they find most appealing" says Keogh. And it is also increasingly influencing the way restaurants behave. "It's not just the dishes that need to be perfectly presented. Instagrammers will also post place settings, menu cards - even images of the bathroom" Keogh continues. 

Social media strategy agencies like Palm PR and Two Forks, which is run by Annica Wainwright and Anna Kibbey, now suggest their clients invest in these types of features.

"Think warm Insta-filter glow, not bright photo studio," Wainwright suggests. Chefs who don't like it, should lump it: "It's not like good-looking food and great lighting is going to upset diners who don't want to post," she says. Besides, adds Kay, it's making restaurants "think more about textures, colours, and plates which in turn influences the taste and experience." Food that looks good, tastes good - that's science, in the form of an 2014 Oxford University report in which diners rated artistically arranged meals as more tasty than simply plated ones - even if the ingredients were the same.