The British Retail Consortium (BRC) has defended its decision to allow Shein to join amid concerns about the treatment of workers.
Scrutiny of the Chinese fast fashion giant is growing ahead of a potential £50bn IPO.
Shein has been criticized for using suppliers that exploit low-paid workers to sell its clothes at low prices.
It has been trying to court the British business community and says it has improved its supply chain.
Concerns: Shein has been criticized for using suppliers that exploit low-paid garment workers in China
This year it became a member of the BRC, which represents around 200 companies including M&S and Burberry.
BRC boss Helen Dickinson said all new members must be “willing to engage” on key issues such as working practices and environmental concerns before being approved.
“The conversation with Shein joining is the same as with any member joining,” he said.
And he said it was not the BRC’s job to defend Shein or act as a “regulator, a policeman, who decides due diligence.”
“We’re not defending any of our members, we’re defending our industry,” Dickinson said. “It is not our job to be responsible for the individual actions of any member.”
Rivals are unhappy that Shein can avoid high customs duties as it ships directly from China.
The fashion brand has said it is investing millions of pounds to improve standards in its supply chains.