Human rights law firm Leigh Day has written to the UK’s Financial Conduct Authority (FCA) to urge the regulator to refuse any attempt by Shein to list on the LSE, it said.

Shein did not immediately respond to a Reuters request for comment, while the FCA declined to comment.

On Tuesday, Amnesty International UK said Shein’s potential London initial public offering would be a “badge of shame” for the London Stock Exchange because of the fast-fashion firm’s “questionable” labour and human rights standards.

Shein confidentially filed papers with Britain’s markets regulator in June, two sources told Reuters on Monday, kicking off the process for a potential London listing later this year.

The company has previously said it was investing in strengthening governance and compliance across its supply chain.

The FCA has no investigation or enforcement powers relating to alleged breaches of legislation not within its remit, such as the Modern Slavery Act or tax legislation.