Asos and JD Sports are facing huge scrutiny of how it treats its workers after the way they operate their warehouses as "inhuman".

One of the GMB union's regional secretaries made the comments after figures compiled by the Press Association showed that an ambulance was called to Asos' Barnsley warehouse 45 times last year, and 40 times to JD Sports' Rochdale site. In fact, over the past three years, Asos has had 117 call-outs and JD Sports 148.

GMB regional secretary Neil Derrick said: “Asos bosses appear to be in denial about the inhuman conditions people have to work under in their Grimethorpe [Barnsley] warehouse.”

Matt Draper, from the Unite union, told Press Association: “The warehouses of some companies risk becoming the dark satanic mills of the 21st century. Where employers work with trade unions and treat people with respect, there are fewer accidents and a better health and safety record.”

It should be noted that the figures relating to ambulance call-outs do not reference the reason behind it.

It is not the first time JD Sports has come under fire for its working practices. It faced an investigation in 2016 after an undercover video led MP Iain Wright to accuse the retailer of treating its warehouse workers like "cattle".

Responding to these fresh questions, JD Sports said: “Given the scale of our operations, the number of incidents where an ambulance is called each year is proportionally very low. If there is a concern that an ambulance may be needed… one will always be called. It would be irresponsible not to.”

Asos and XPO Logistics, which manages the warehouse, said: “We are a responsible employer that values the safety and the welfare of our 4,500 Grimethorpe site employees above all else. It is our policy to call an ambulance whether a situation is work-related or not, often as a precaution.”

In 2016, a group of MPs described Sports Direct's warehouses as "Victorian warehouses", having already discovered that workers were effectively being paid below minimum wage. The figures compiled by the Press Association found a vast improvement in ambulance call-outs at its Shirebrook site. Having reached more than 140 call-outs in just 2013 and 2014, there were just nine in 2018.