The U.K. Financial Reporting Council (FRC) fined Big Four firm PwC more than 5.6 million pounds (U.S. $6.6 million) for failing to challenge management, obtain sufficient evidence, and follow basic requirements while conducting audits of a British defense contractor and its subsidiary.

The FRC’s final settlement notice, made public Wednesday but issued Jan. 3, also fined two former PwC audit partners for their work at Babcock International Group for the fiscal years ended 2017 and 2018 and Babcock subsidiary Devonport Royal Dockyard for FY2018.

The FRC said its investigation of the audits of Babcock and Devonport found “numerous, serious breaches” of U.K. auditing standards. Deficiencies included “repeated failures to challenge management and obtain sufficient appropriate evidence” and “failure to follow basic audit requirements, evidencing a lack of competence, care, or diligence,” the regulator said in a press release.