The FCA has refused to publish a full report into past allegations of mistreatment of business customers by the Royal Bank of Scotland.
The leaked report, the FCA said, would have revealed confidential information about business customers that have been mistreated by the UK bank from its former Global Restructuring Group.
The GRG was set up by RBS between 2005 and 2013 and was intended to help businesses facing financial distress.
However, the FCA analysis, seen by the BBC in August, shows the firms placed in the group had to pay unnecessary fees and had struggled to return financially healthy.
At that time, RBS denied the accusations.
Meanwhile the newly appointed chair of the Treasury Select Committee Nicky Morgan has urged the FCA for the release of the full report.
Morgan said holding back on the document was “unsustainable” given the “overwhelming” public interest in the publication, the BBC reports.
The FCA said it will only publish a summary the reports’ findings.
Chief executive Andrew Bailey said in a letter to Morgan that the content of the watchdog report was not in the best interest of the public.
Morgan said in a statement: “The committee recognises that such reports are not intended for publication, and should in normal circumstances remain confidential.
“But the report is now in the hands of an unknown number of third parties.
“If closure is ever to be brought to this long-running issue, parliament and the public need the account ordered by the regulator.
“And so we consider that the public interest in publication in this specific case is overwhelming.”
The TSC said it will go ahead in the scrutiny of the GRC scandal, the way the FCA has handled it and to make sure banks have their contingency plans in place regarding the exit of the UK form the European Union.