An official investigation is to be launched into practices at troubled supermarket giant Tesco including delays in payments to suppliers.

The move was announced by the Groceries Code Adjudicator (GCA) in the UK, Christine Tacon, who said she had formed a "reasonable suspicion" that the retailer has breached supply guidelines.

She said she took the decision after considering information submitted to her following Tesco's profit over-statement last September.

She has discussed the practices with Tesco and will now seek more information from direct suppliers and others to determine what further action to take.

The post of Adjudicator was set up in 2013 to monitor the relationship between the 10 largest retailers and their suppliers.

The investigation, the first to be held, is expected to take up to nine months, and the Adjudicator has called for evidence to be submitted by 3 April.

It will cover the conduct of Tesco plc from 25 June 2013 (when the GCA was created) to 5 February this year.

A statement said: "The investigation will consider the existence and extent of practices which have resulted in delay in payments to suppliers. This will include in particular, but not be limited to, 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
• Deductions in relation to historic promotions which had not been agreed."

The investigation, which follows a catastrophic period for Tesco including store closures, will also look into suppliers having to make payments for better positioning of goods on shelves not related to a promotion.

Initially the probe will be restricted to Tesco but could be expanded to include other supermarkets if warranted.

Ms Tacon said: "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."

A Tesco spokesman said: "We have taken action to strengthen compliance and... we are changing the way we work with suppliers.

"We will continue to co-operate fully with the GCA as she carries out her investigation and welcome the opportunity for our suppliers to provide direct feedback.”

Business Secretary Vince Cable said: "This is an historic day for the groceries code adjudicator and shows we have created a regulator that has real teeth.

"I would encourage anyone with any evidence of wrongdoing to come forward and to be confident of being able to do so confidentially as their anonymity will be protected by law."