Fast-fashion giant Shein is set to miss out on a spot in the UK’s FTSE 100 index, which lists the UK’s top firms by market value, according to reports.

City sources said the number of shares sold is expected to “fall short of the minimum required to qualify for inclusion”, according to The Sunday Times.

Rules set by the London Stock Exchange mean companies incorporated outside the UK must have a minimum free float of 25%.

The potential of Shein listing on the London Stock Exchange has continued to spark debate and the British Fashion Council has become the latest trade body to flag the potential listing as a “significant concern” to the City.

British Fashion Council chief executive Caroline Rush told the Mail on Sunday: “At a time when global fashion leaders are rightly focused on making our sector more socially, environmentally and economically sustainable, the government’s courting of Shein to list on the London Stock Exchange, and Shein’s decision to do so, is of significant concern to UK fashion designers and retailers.

“Whilst we appreciate that Shein has committed to meeting acceptable industry standards, questions remain about the ethicality and sustainability of a business model and supply chain that consistently undercuts British designers and retailers, and these still need to be answered.”

This comes after The Guardian reported that workers’ rights campaigners are calling on the next UK government to stop Shein joining the FTSE.

Labour Behind the Label campaigns lead Alena Ivanova said it had reacted to the news of British politicians supporting the listing “with dismay” due to Shein’s “lack of transparency about its supply chain and ethical concerns”.

UNI Global Union head of commerce Mathias Bolton also told the newspaper that Shein “shouldn’t be rewarded with the credibility of being listed in the City, or anywhere else, given the lack of transparency in their supply chain and shocking reports of severe labour violations”,

A Shein spokesperson said it “has a zero-tolerance policy for forced labour and we are committed to respecting human rights. We take visibility across our supply chain seriously and have invested millions of pounds in strengthening governance and compliance.”

The retailer said its supplier audits show “a consistent improvement in performance and compliance”, as well as “improvements in ensuring that workers are compensated fairly for what they do”.