Troubled supermarket giant Tesco is to be investigated by the Financial Conduct Authority (FCA) for overstating profits by £250m.

The company revealed the accounting irregularity last week and launched its own investigation via Deloitte.

Tesco said it would “continue to co-operate fully with the FCA and other relevant authorities considering this matter”.

The supermarket has suspended four executives in connection with its accounting problems, including its UK managing director Chris Bush.

Commenting on the overstating last week, Dave Lewis, group chief executive, said: "We have uncovered a serious issue and have responded accordingly. The chairman and I have acted quickly to establish a comprehensive independent investigation.

“The board, my colleagues, our customers and I expect Tesco to operate with integrity and transparency and we will take decisive action as the results of the investigation become clear.”

Tesco has had a torrid time of late, with falling sales, the installation of a new chief executive and a shares fall following its admission on profits.

The Financial Reporting Council, the accountancy watchdog, and the Serious Fraud Office are also understood to be monitoring events at the group.