The identity of the new owner of British Steel was once again in doubt on Wednesday as the Official Receiver responsible for selling the business said it will start talking to other potential suitors.

The decision by the Government’s Insolvency Service comes as a two-month period of exclusive talks between the department and Ataer Holding ends this week.

The Official Receiver said: “While discussions with Ataer are continuing, discussions with other parties who have expressed continued and renewed interest in acquiring the whole British Steel business will now be possible.

“I have instructed the Special Managers to engage with these additional interested parties. Diligence team members from these parties are expected to visit the company’s sites over the coming days and weeks.”

Previous reports have suggested that investment vehicle Ataer, which is controlled by Turkey’s military pension fund, is concerned at the lack of progress to push through price cuts with suppliers.

But the Official Receiver insisted: “Ataer remain very much interested in acquiring the business and we remain in detailed discussions with them to conclude a sale.”

The news is expected to cause concern among British Steel’s 5,000 staff, including 4,000 at its plant in Scunthorpe, and a further 700 on Teesside in north-east England.

The company is also indirectly responsible for 20,000 workers in the supply chain and produces around 2.5 million tonnes of steel a year.

The Unite union called on Business Secretary Andrea Leadsom to guarantee the Government’s continued support for British Steel and honour previous commitments on research and investment necessary to facilitate the smooth sale of the steelmaker.

Assistant general secretary for manufacturing Steve Turner said: “I have written to the Business Secretary Andrea Leadsom requesting an urgent meeting.

“It is vital that the Government continues to stand behind British Steel until the sale process is finalised to maintain customer, supplier and workforce confidence in a company which can have bright future.

“This includes honouring commitments on research and investment which assist the smooth sale process of British Steel and a recognition that the success of the steelmaker is central to any future UK industrial strategy.”

Ataer, which invests funds for the Turkish Armed Forces Assistance Fund – or Oyak – already owns nearly 50% of Turkey’s biggest steel producer, Erdemir.

However, there has been criticism that the company is too close to the Turkish government and lacks accountability.

British Steel was put into compulsory liquidation in May after talks between previous owner Greybull and the Government collapsed, leading the business to be run by the Official Receiver.

Previous reports had suggested that Oyak wants to buy British Steel as the first step to buying up steel assets across the world.