Accounting watchdog the Financial Reporting Council (FRC) has launched an investigation into the auditing of Tesco’s financial statements for 2012, 2013 and 2014.

The retailer’s accountancy firm PwC will also come under scrutiny as the external auditor involved in preparing and signing off accounts for the years ended 25 February 2012, 23 February 2013 and 22 February 2014.

Tesco’s disastrous interim results in September, in which the retailer dramatically revealed it had discovered a £250m black hole in its accounts, will also be investigated.

The figure was revised in October to £263m following an internal examination led by CEO Dave Lewis, compounding a miserable run of profit warnings for the supermarket giant.

“We note the Financial Reporting Council is launching an investigation into individuals and a member firm in relation to the preparation, approval and audit of our accounts for the last three years,” said a Tesco spokesman. “We will provide support to the FRC’s investigation. 

The FRC’s investigation is the latest external probe into Tesco’s accounting practices and follows the Serious Fraud Office launching its own inquiry into the scandal in October.

The SFO is understood to be preparing to widen its remit, dragging in some of the retailer’s biggest UK suppliers, such as Diageo and Unilever, who will be interviewed in early 2015.

Part of the inflated profit in Tesco’s half-year figures were the result of rebates from suppliers being brought forward.

A spokesman for the SFO said the government agency was unable to provide running details on the case but added the criminal investigation into the accounting practices of Tesco was ongoing.