Groceries Code Adjudicator Christine Tacon has urged suppliers to come forward with “hard evidence” to allow her to investigate alleged breaches of the Code, in the wake of controversy over Tesco’s dealings with suppliers, running up to its £263m black hole.

In an appeal to suppliers this week, Tacon said she would be hamstrung in any potential investigation of Tesco unless suppliers came forward with more than just anecdotal evidence.

“This month there has been increased interest in the GCA’s role as a result of the Tesco’s financial reporting announcement, and I am considering what action to take,” Tacon said in a newsletter.

“I believe the GCA is well placed to make a difference. However, the reality is that the GCA cannot achieve significant change alone.”

With Tesco already under investigation by the Serious Fraud Office, MPs including business secretary Vince Cable have been pressing for a full scale investigation into the relationship between Tesco and suppliers, with some MPs suggesting it should extend to the wider industry.

“We are working closely with the retailers’ code compliance officers to bring about change –- but my message to suppliers is that you have responsibilities too,” said Tacon.

“First, you have to bring hard evidence to me about practices you believe breach the Groceries Supply Code of Practice. Without a strong body of fact-based information I cannot launch an investigation or prove a breach of the Code has taken place. So if you genuinely want me to use my powers to tackle the issues in this sector then the responsibility lies with you to give me the evidence to act. “

Tacon also called on suppliers to “help accelerate change by challenging the practices that have grown up in the sector”

“A better approach for suppliers and retailers would be to make the supply chain simpler and more efficient and both sides have a role in that,” she said.

Yesterday, it emerged business secretary Cable had expressed concerns about Tesco’s treatment of suppliers in a move which will increase the scrutiny still further on the criminal investigation into the circumstances leading up to the £263m black hole in its accounts.