The Financial Reporting Council (FRC) has launched an investigation into whether Grant Thornton, auditors to soft drinks group, Nichols plc, was independent at the time of conducting the audits of the company's financial statements for the years ended 31 December 2011 and 2012.

Grant Thornton earned £60,000 for auditing financial statements for the year ended 2012, up from £38,000 for the audit of the financial statement for 2011.

In a statement, the firm said: 'We acknowledge the FRC's statement regarding their investigation. 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.'

In a statement, Nichols said: 'We note the FRC announcement this morning and Grant Thornton's subsequent statement. At this stage we have no further comment to make.'