Liquidator FRP Advisory has launched a claim against the accountancy firm, alleging it was 'negligent' in the preparation and conduct of Patisserie Valerie's financial statements between 2014 to 2017.
The claim has come to light in a report to creditors of Patisserie Valerie from FRP, which was filed in December.
FRP said 'large accounting misstatements' resulted in Patisserie Valerie's board 'being unaware that the group has insufficient funds to continue to trade'.
Grant Thornton audited Patisserie Valerie’s accounts for 12 years until the chain collapsed into administration in January 2019.
A Grant Thornton spokesperson said: “We will rigorously defend the claim.
"Patisserie Valerie is a case that involves sustained and collusive fraud, including widespread deception of the auditors. The claim ignores the board’s and management’s own failings.
“As the matter is subject to an ongoing FRC investigation and civil claim, we are unable to comment further.”
Patisserie Valerie collapsed into administration back in 2019 following the discovery of a multi-million-pound black hole in its accounts.
It was subsequently sold to Irish private equity firm Causeway Capital Partners.
The Serious Fraud Office is investigating the 'business and accounting practices of individuals' associated with Patisserie Valerie and six people are known to have been arrested, including one re-arrest.
The Financial Reporting Council is also investigating the audit by Grant Thornton.