Bloom's restaurant in Golders Green has gone into liquidation.
It has been closed since Sunday and a notice on the door asks creditors to contact insolvency firm David Rubin and Partners. A creditors' meeting is being held on June 25.
The iconic Bloom's restaurant in Whitechapel opened in 1920 and closed in 1996. The Golders Green branch opened in 1965 and was renovated in 2007.
An Edgware outlet launched in 2007 lasted only a year.
A Bloom's waiter, who asked not to be named, said he had not been paid for six weeks - and some colleagues had gone unpaid for longer.
"I turned up on Sunday and talked to the manager who said it had closed down. Some staff had refused to work because they weren't being paid so they had to shut. I just had to go home after that."
Rabbi Jeremy Conway of the London Beth Din kashrut division said: "Bloom's has flown the flag for kosher restaurants for the best part of a century. We are saddened to learn of its demise.
"However, we must see this sad news in the context of the constant growth of the kosher restaurant scene in London.
"There are now some 15 kosher establishments lining the block for so long dominated by the Bloom's emblem. The ever-increasing number and variety of kosher restaurants is exciting and testimony to the vitality of Jewish life in London."
Jonathan Tapper, the last link with the Bloom family, said the closure was "very sad and the end of an era. But it's nothing to do with the family since the business was sold. It's a shame that the name could not continue."