The Financial Reporting Council (FRC) launched an investigation into Grant Thornton UK’s auditing of soft drinks maker Nichols.
The FRC will look at whether Grant Thornton UK was independent when it conducted the audits of Nichols financial statements for the two years up to December 2012.
Grant Thornton UK said in a statement: "The FRC and Grant Thornton have a common interest in promoting good corporate governance and reporting standards. We shall, of course, fully cooperate with any investigation. As a firm, we continue to strive to deliver quality work for our clients and other stakeholders and go to great lengths to maintain our independence".