Tesco is being probed by the newly formed Groceries Code Adjudicator (GCA) for its treatment of suppliers.
Newly created in June 2013, head of GCA Christine Tacon has joined the Serious Fraud Office and the Financial Reporting Council to investigate the supermarket chain. The adjudicator says it had "reasonable suspicion" that Tesco has breached the Groceries Supply Code of Practice.
The announcement came in the wake of information submitted to Tacon related to practices associated with the profit over-statement announced by Tesco in September 2014.
The probe will cover the conduct of Tesco from 25 June 2013 to 5 February 2015 and focus on practices which have resulted in delay in payments to suppliers. Expected to take place over the next six to nine months, GCA requires the evidence to be submitted by 3 April 2015.
This will include delay in payments associated with short deliveries, including imposition of penalties; consumer complaints where the amounts were not agreed; invoicing discrepancies such as duplicate invoicing where two invoices were issued for the same product; deductions for unknown or un-agreed items; deductions for promotional fixed costs (gate fees) that were incorrect; and deductions in relation to historic promotions which had not been agreed.
Existence and extent of practices where suppliers have been required to make payments for better positioning of goods (shelf-positioning) which are not related to a promotion will also be probed.
Commenting on the development, Christine Tacon said: "This is the first investigation I have launched and it is a significant step for the GCA. I have taken this decision after careful consideration of all the information submitted to me so far.
"I have applied the GCA published prioritisation principles to each of the practices under consideration and have evidence that they were not isolated incidents, each involving a number of suppliers and significant sums of money."
Tacon noted that other supermarkets could also be probed if during the investigation, similar practices carried out by other retailers are uncovered.
However, the GCA will not be able to fine Tesco for past offences, said Tacon while talking to BBC.