By Paul Sandle

LONDON (Reuters) -Britain's business secretary said a London listing set a "gold standard" in terms of environmental, labour and tax regulation, countering any risk of moral hazard, when asked about Chinese online retailer Shein's intention to float.

Jonathan Reynolds' signal of support for the IPO came after London was dealt a blow when Unilever chose Amsterdam for the main listing of its ice cream business on Thursday.

Shein confidentially filed papers with Britain's Financial Conduct Authority (FCA) in June last year, sources have told Reuters. But it has taken longer than typically expected for the regulator to sign off on a listing that could value the company at $50 billion.

Reynolds said the FCA made decisions about listings so he was speaking in abstract terms.

"Our aspiration should be if there's a business doing a lot of business in the UK, the gold standard for us is regulating from the UK," he told reporters after a speech on Thursday.

Shein has faced allegations that it uses cotton from China's Xinjiang province, where the United States has accused the Chinese government of human rights abuses. Beijing denies any abuses.

It has also been accused of damaging the environment and avoiding tax, prompting some UK lawmakers to question its suitability for going public in the UK. Shein refutes these allegations.

Reynolds said: "If we have any concerns about any company, the best way to make sure we don't have those concerns in the future is to regulate them here in the UK.

"So I don't see (a listing) as a moral hazard or controversial."

Reynolds said he had wanted Unilever to opt for London, where it has its main listing.

"We do a lot of work talking to a range of businesses to make sure they understand the political desire for them to come to the UK," he said.

Pension reforms were one example of the steps the government was taking, he said.

"But I feel we will not maybe turn around some of the sentiment until we've got some of those high profile success stories," he said. "I would have liked Unilever in the UK."

(Additional reporting by James Davey, writing by Paul Sandle and Muvija M, editing by Catarina Demony, Alexandra Hudson)