The Serious Fraud Office has opened a criminal investigation into Tata Steel’s UK operations, reports The Independent.
Police officers are investigating allegations staff tampered with certificates detailing the composition of the steel products before they were sold.
The company’s Yorkshire site is the focus of the inquiry, the Daily Telegraph reported.
At least nine employees have been suspended and around 500 clients, including BAE and Rolls-Royce, are thought to be affected.
There is also a trading standards investigation, but it is unclear whether it is linked to the criminal investigation.
Tata Steel announced it had put its entire UK business up for salefollowing a board meeting in Mumbai, putting thousands of workers’ jobs at risk.
The company said the move was to stem heavy losses from high manufacturing costs, competition with China and a global oversupply of steel.
Ratan Tata, the former chairman of Tata Group, defended the decision, calling the UK steel operation “underinvested and overmanned”.
In January, Tata announced more than 1,000 job losses at UK plants, 750 of them in Port Talbot.
That came after 1,200 job losses at Tata plants in Scunthorpe and Lanarkshire last October, at the same time steel manufacturer SSI closed another plant at Redcar.