The Big Four accountancy firms will face “more intrusive” scrutiny, according to KPMG’s ex-UK boss Mary O’Connor, as her former employer battles one of the most turbulent periods in its 150-year history. 

KPMG is facing questions over its audit work on Silicon Valley Bank which collapsed on 10 March, two weeks after the Big Four firm approved the lender’s accounts. Within two days, US regulators also closed Signature Bank — 11 days after KPMG gave them a clean bill of health. In March, KPMG said it stands by its audits of the two banks.