Transline, an employment agency that was involved with Sports Direct, has submitted court documents preparing for insolvency. Now Sports Direct is being urged to put agency workers onto permanent contracts.

Transline said it was close to securing inward investment, but lodged a Notice of Intention to protect its business.

The Yorkshire-based firm, and a second agency, the Best Connection, have been entangled in the controversy over pay and working conditions at Sports Direct's warehouse in Shirebrook, Derbyshire.

A Transline spokesman said: "The company has suffered as a result of a continued move to tighter margins in the recruitment industry. We are close to securing inward investment that will allow us to drive forward with continued growth and infrastructure development, and have lodged the Notice of Intention to protect the business, our employees and our customers as we complete this process.

"The welfare of our staff and our relationships with our customers are of paramount importance and we are continuing our service and operations as normal. We expect to hear more regarding potential trading investments imminently."

Unite assistant general secretary Steve Turner also commented: "The current uncertainty surrounding Transline's future is yet more evidence of the need for Sports Direct to wean itself off its over reliance on temporary agency workers at its Shirebrook warehouse.

"Sports Direct must urgently move to put agency workers onto permanent contracts to bring security to the workforce and certainty to the business,” Turner said. “Transline must not be allowed to dodge its responsibilities or the back pay it owes for non-payment of the minimum wage at Sports Direct.”

"It must continue to pay the wages of the tens of thousands of low-paid agency workers it currently employs across the UK,” Turner said. “A failure to do so would be the final insult for the many workers it has exploited through its draconian work practices."

Neil Derrick of the GMB said Transline had been the "ugly face of the gig economy" in recent years and had been at the heart of the union's campaigns against the exploitation of workers and precarious employment.

"They were the agency supplying workers to Sports Direct, they were sacked by Amazon and they are still supplying casual workers to Asos in Barnsley,” Derrick said. "Let's hope the business model of making a quick buck on the back of hiring and firing people looking for work dies with them. What workers really need is the hope of secure employment and certainty of income."