The London Stock Exchange (LSE) has been asked what checks are in place to vet firms after fast-fashion retailer Shein refused to answer “basic questions” over its supply chain.

Liam Byrne, chair of the Business and Trade Committee, wrote to Dame Julia Hoggett asking if the stock market had tests in place to “authenticate statements” by firms seeking to list, “with particular regard to their safeguards against the use of forced labour in their products”.

It comes after MPs branded the evidence of a Shein lawyer “ridiculous” when she refused to say if the company sold products containing cotton from China.

Byrne told Dame Julia that MPs were “profoundly concerned at the lack of candid and open answers”.

“The committee would like to draw your attention to the concerning evidence we heard,” he said in a letter to the LSE chief executive on Friday.

The BBC understands Shein, founded in China but now headquartered in Singapore, has filed initial paperwork to list in the UK, which could value it at £50bn. It follows the retailers rapid rise to one of the biggest fast fashion firms globally, shipping to customers in 150 countries.

But questions remain over the company’s supply chain amid allegations of forced labour and human rights abuses.

During an appearance in front of the Commons’ Business and Trade Committee on Tuesday, a senior lawyer representing Shein, Yinan Zhu, repeatedly refused to say whether the company sold products containing cotton from the Xinjiang region – an area in which China has been accused of subjecting Uyghur Muslims to forced labour. Shein has denied the claims.

Ms Zhu declined to answer and asked if she could write to the committee following the hearing.

Her repeated refusal to answer questions about supply chains and a potential UK listing, was met with backlash from the committee of MPs, who accused her of “wilful ignorance”.