By Daniel Hunter
Tesco has launched an independent inquiry after discovering it had overstated its profit forecast by £250 million.
Tesco has suspended four executives, including UK managing director Chris Bush.
"We have uncovered a serious issue and have responded accordingly," Dave Lewis, who only started his role as Tesco chief executive at the start of September, said.
Mr Lewis said he wanted Tesco "to operate with integrity and transparency".
"We will take decisive action as the results of the investigation become clear."
The overstated profits referred to its profits for the six months to 23 August. Tesco had forecast profits of £1.1bn for this period, but it is now expected to be at least £250m less.
In a statement, Tesco said the overstated forecast was "principally due to the accelerated recognition of commercial income and delayed accrual of costs" and "in-year timing differences".
The company's share prices plummeted by more than 10% in early trading on the London Stock Exchange.
Deloitte will now lead the independent inquiry.
Tesco was due to publish its results for the period on 1 October, but this has been pushed back to 23 October.
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