The controversy surrounding undisclosed payments to Ryan Turbidy has now expanded to include commercial dealings after a whistleblower alleged that RTÉ had paid €50 million in kickbacks over ten years.

The anonymous source claims the same account used by RTÉ to make the undisclosed payments to Tubridy was also used to funnel over €50 million credit note payments to ad agencies over the past decade.

The news comes after Media Minister Catherine Martin's announcement of an external review following a crisis meeting with Chair of the board Siún Ní Raghallaigh on Friday.

The source told the Independent that the Turbidy payments were "the tip of the iceberg when it comes to payments made by RTÉ by way of secretive credit notes."

Another anonymous media source told the Sunday Independent that presenters were compensated for appearances with "free cars," calling it "not really appropriate."

Though credit notes, commonly referred to as kickbacks, are illegal in the US, they remain widespread in the Irish media landscape according to the source.

RTÉ released a statement in response to the news, saying the broadcaster "is satisfied that the manner in which it grants discounts is compliant with competition law." Adding, its auditors "have reviewed commercial income as part of their annual audit and that no issues have been raised in relation to controls over volume discounts."

RTÉ claims as a dual funded agency (receiving funding from both licensing fees and advertisers), it receives 45pc of funding from commercial agreements, adding that their funding model "was recently reaffirmed by the Future of Media Commission."

The statement also reiterated "The Broadcasting Act, which is the statutory basis that underpins all of RTÉ’s activities, obliges RTÉ to maximise the commercial opportunities that arise in pursuit of its public service activities. RTÉ is assessed each year by the media regulator (until recently the BAI, now Comisiún Na Meán) to ensure it is maximising its commercial revenues."