Once hailed as the saviour of British steel, Sanjeev Gupta and his business empire are now at the centre of an investigation by the Serious Fraud Office.

The SFO has announced a probe into suspected fraud and money laundering at GFG Alliance, which has thousands of staff in the UK, including at Liberty Steel.

It is another twist in a long journey for Mr Gupta, who was born in India but was sent to boarding school in the UK when he was 12.

An early starter, the businessman formed a chemicals trading business when he was at Cambridge University and was generating as much as £1 million a day before he had graduated.

He later branched out into buying steel mills, starting in Africa and Asia before turning his eye closer to home.

Mr Gupta started forging his reputation in the UK when he bought a struggling steel mill in South Wales, saving it from likely collapse and rescuing jobs.

He went on to relive this success several times, snapping up sites in the UK’s struggling steel industry and turning them around.

Most famously his 2016 deal with Tata Steel was estimated at the time to have saved around 1,700 jobs, earning him plaudits in the press as the “great hope” of the British steel industry.

GFG Alliance now employs 35,000 people in 30 countries, with revenues of around 20 billion dollars (£14 billion) a year.

However the way it is financed has come under the microscope in recent years.

Some old questions, and some new ones, were thrown into the spotlight when Greensill Capital collapsed in March.

GFG used so-called supply chain finance services offered by Greensill. This meant that if GFG sold a product to a different company, it could send the invoice to Greensill and be paid right away, rather than having to wait potentially months for the customer to pay its bills.

Bringing in money this way can be useful for companies with tight cash flows.

However, how Greensill and GFG did business together is being investigated by fraud investigators.

It is likely to spark renewed fears for the future of GFG’s employees.