High street restaurants are closing up and down the country - Prezzo, Carluccio's and Jamie's have all announced they are closing branches. But last week saw another casualty - and this one really hurt.

The Delisserie, a favourite haunt for many north west Londoners with its menu of Ashkenazi staples, has gone into liquidation after 15 years.

The doors closed on their Borehamwood, Temple Fortune, Stanmore and St Johns Wood restaurants for the final time. Where's a girl going to get her haimish fix now?

I spoke to owner, Justin Davies, who founded the businesses with brother Ian Davies. He blamed a number of factors for his company's demise.

"The restaurant business is in absolute turmoil. Rent, rates and wages have all increased and ever since the Brexit vote, food costs have spiralled. The slide started the day after" he told me.

He also blamed the culture of discounting: "Customers are spoilt for choice these days and discounting is what is killing the trade" he said. "Who goes out for a pizza without a discount voucher?"

"On top of that the venture capitalists are opening hundreds of stores which saturate the market and then we lose more trade to Deliveroo. People eating delivery food don't come in and spend on drinks and we then also have to pay a cut to Deliveroo. Open the paper every day and there's another casualty!"

That aside, the biggest problem Davies blames for The Delisserie's misfortune is the arrival of keyboard warriors on social media. He feels particularly sore about some comments on one Facebook group, The Restaurant Club, which has 21,660 members, many of whom are based in north west London - in particular those suggesting that his menu was too big to be really fresh food.

A few weeks ago, to answer the doubters, Davies decided to slim down his menu.

"We reduced it down to almost nothing. The small menu was much harder to implement than the big menu. The larger menu had been a make-up of the same base ingredients, mixed and matched, which meant everything sold, nothing sat and everything was fresh. The smaller menu was more difficult than the bigger menu because we were trying to make every dish different."

Davies says that the new smaller menu lost him trade. "Our loyal customers alienated us from the day that smaller menu went in. On the day that smaller menu went in our turnover dropped off a cliff. That online advice killed us."

I asked Davies why he listened to the keyboard critics. "Because they are our customers. You got to try to change the perception, of 25,000 people thinking all your stuff is coming out of the freezer. We were just in a catch 22 - we couldn't win. We gave them the small menu and with eight weeks of poor trading, we were in a hole that you can never get out of."

"It was a nightmare. I never wanted to be spoken about, good or bad. I just wanted them to stay away from me. But we became the joke of north London."

"You plant the seed and now you've got customers coming into the restaurant searching to find fault, and you'll always find fault of you look hard enough."

"The Restaurant Club had a major impact. It didn't kill us off but it didn't help. The frustrating part of our business was that we never made money from it ever. Ever. I've got a huge weight off my shoulders now. To run a business and to battle and not make money from it, to have all the headaches that we did."

I spoke to Louisa Walters, founder of The Restaurant Club, who said: "It is unfortunate that Delisserie has now closed, but we know that our members will continue to support independent restaurants in these challenging times. The group is an open forum for foodies to share their news and views."

She feels the Club is a positive force for independent restaurants:  "We have a discount scheme which drives thousands of cardholders into hundreds of independent restaurants, saving the diners money and keeping the restaurants busy and there are several restaurants in north London that attribute their continued success to the group. We actively encourage constructive comments and we always give the opportunity for restaurateurs to respond to both happy and not so happy diners."

Davies plans to continue wholesaling salt beef to customers. "I was supplying 2000 kg of salt beef a week. All the salt beef that these people are raving about everywhere else is my salt beef."

Is London simply falling out of love with old-school delis in the same way New York has said goodbye to several of its most famous salt beef bars in recent years? Davies thinks not. "No, if anything Jewish food has become a much bigger product. Everywhere you go, all these foodie outlets, stalls and street vendors are selling it. It's become a very cool product."

For now, Davies will be licking his wounds and hopes to continue sell his salt beef, pastrami, latkes and chicken soup to other businesses. "I hear from my suppliers that customers think it's the best thing ever - it's so ironic."