Five more people have been arrested in the investigation into the collapse of British cafe chain Patisserie Valerie after accounting irregularities were discovered last year, the Serious Fraud Office (SFO) has said. 

The new arrests bring the total to six. 

Patisserie Holdings' former finance director Chris Marsh, who had helped grow the company from eight stores to more than 200, was arrested and released on bail over the scandal last year. 

Police did not name those arrested this month. 

"On Tuesday 18 June, as part of a joint operation with Hertfordshire, Leicestershire and the Metropolitan Police Services, five individuals were arrested and interviewed in connection with the Serious Fraud Office investigation into individuals associated with Patisserie Holdings," the SFO said in a statement. 

The chain was plunged into crisis in October 2018 when it discovered accounting irregularities and said tax authorities were pursuing its main trading arm for more than £1m. 

KPMG was appointed as the administrator, and in February the bakery chain was sold to Irish private equity fund Causeway Capital and the Philpotts brand to food retailer AF Blakemore. 

Britain's accounting watchdog, the Financial Reporting Council, said in November it was investigating Grant Thornton's audit of Patisserie Valerie for 2015-2017. 

Grant Thornton announced its own independent review and a £7m revamp of its UK accounting operations earlier this month to improve standards. 

Patisserie Valerie's former executive chairman Luke Johnson was not one of the five arrested, the Sunday Times said.

Johnson is a columnist for the newspaper's business section.