Up to 3,000 jobs are likely to be affected as Frankie and Benny’s owner The Restaurant Group (TRG) is set to permanently close between 100 and 120 restaurants.
The PA news agency understands that the company, which also owns Wagamama, will not reopen these sites to customers when lockdown restrictions unwind.
The majority of these closures will affect Frankie and Benny’s sites, with smaller sister brands such as Garfunkel’s also affected.
Between 2,000 and 3,000 jobs are believed to be impacted by the move.
It is understood that Wagamama sites will not be affected.
The dining group said last year that it would close up to 150 sites in its leisure division, which includes more than 200 Frankie & Benny’s restaurants, over the next five years.
But sources close to the company said it had been “forced to accelerate” its plans as a result of the coronavirus outbreak.
Earlier on Wednesday, an email seen by the BBC said the group was set to tell staff that many sites were “no longer viable to trade and will remain closed permanently”.
The email adds: “The Covid-19 crisis has significantly impacted our ability to trade profitably, so we’ve taken the tough decision to close these restaurants now.”
In March, TRG was forced to shut 60 of its Chiquito Mexican-style outlets as well as its Food & Fuel chain of pubs in London after falling into administration.
The company, which currently has around 22,000 staff on furlough, is one of the largest restaurant operators in Britain.
TRG declined to comment.
Shares in the company jumped by more than 12% on Wednesday in response to reports over the closure proposals.