London bankers have waited more than two years for initial public offerings to bounce back. When news of fast-fashion upstart Shein’s potential listing first emerged at a potential £50 billion ($64 billion) valuation, the City saw a deal that could finally reverse the slump.

It won’t be easy. To deliver what could be one of the U.K.’s biggest-ever IPOs, the controversial e-commerce retailer will need to convince regulators, politicians and investors that it meets their standards for inclusion.

Critics warn that a Shein listing in London would make the City into a market of last resort. They point to allegations about the company’s environmental, social and governance record, including allegations highlighted by U.S. politicians that the China-founded firm’s products are linked to forced labor. Shein has said it has a zero-tolerance policy for forced labor.