The regulator confirmed it would be powerless to pass on any fines to the HBOS executives because of the time taken to complete the investigation in what led to the collapse of the mortgage lender.
The review was first launched by the Financial Services Authority (FSA) in September 2012 following the enforcement proceedings against Peter Cummings, ex-head of corporate banking. When the review was taken over by the FCA and the Prudential Regulation Authority they announced they would publish the report at the end of 2014.
But, a process called Maxwellisation which allows firms and individuals cited in the report a right of reply, is said to have held up the final publication.
A report on Sky News said a six-year statute of limitations meant that the regulators were now unable to impose fines on those investigated during the 2004 to 2008 period covered by the probe.
The FSA’s supervision of the bank is expected to be severely criticised.
The final report is due to be published on Thursday along with Andrew Green QC’s report into the FSA’s enforcement actions following the failure of HBOS.