DW Sports, a gym and sports retailer, has said it will enter administration, putting 1,700 jobs at risk.
The company, founded by former Wigan Athletic owner Dave Whelan, operated 73 gyms and 75 stores across the UK.
All of its stores are to close, but DW said it would work with administrators to save as many gyms as possible.
Fitness First and its 43 gyms, which are part of the same group of companies, will not be affected, the firm said.
“As a consequence of Covid-19, we found ourselves in a position where we were mandated by government to close down both our retail store portfolio and our gym chain in its entirety for a protracted period, leaving us with a high fixed-cost base and zero income,” chief executive Martin Long said.
“The decision to appoint administrators has not been taken lightly but will give us the best chance to protect viable parts of the business, return them to profitability, and secure as many jobs as possible.”
DW Sports had already closed 25 of its stores, and the firm said its remaining 50 retail sites would “all be moving into closing down sales from today”.
The DW Sports website will cease trading with immediate effect.
The company said 59 of its gyms in England and Northern Ireland have reopened, while 14 are in areas restricted by localised lockdowns and are closed.
Mr Long told the BBC in April that the firm’s income normally totals around £15m a month, but that it had fallen to zero, overnight, while it still had a £3m monthly wage bill.