TESCO’S “mafia-like” practices towards suppliers will face an official probe with the prospect of big fines, the new supermarkets watchdog announced yesterday.

Grocery code adjudicator Christine Tacon will look into complaints that the transnational firm has been delaying payments and even wrongly docking cash from invoices for thousands of undelivered items.

She said that suppliers had told her of cases where they had billed for a delivery of 100,000 items but been paid for 80,000 with Tesco claiming the other 20,000 were not supplied.