THE long-awaited and potentially explosive report into the 2008 downfall of Halifax Bank of Scotland, HBOS, due shortly after the General Election, is to be delayed yet again and might now not be published until the end of the year, more than three years after it was commissioned.

The SNP said the continuing delay was "unacceptable," noting: "Justice delayed is justice not done."

Senior sources at the Financial Conduct Authority, which is overseeing the report, said that the so-called Maxwellisation process, whereby anyone criticised in the report has a right of reply before publication, meant that the report's findings will have to be put back several months further.

One insider said: "There is still a process of Maxwellisation going on; which is going to take some time. I'd be very surprised if we got something out this side of summer. It's not looking like we'll get anything before October; it could be more towards the end of the year."

He explained the process of Maxwellisation - named after an investigation into the late media tycoon Robert Maxwell's business empire - was a lengthy and involved one because responses to those criticised in report led to more responses and calls for changes to the text of the report.

Among those expected to face stern criticism in the FCA report are James Crosby, the bank's chief executive during a rapid period of growth, Lord Stevenson, the former chairman, and Andy Hornby, who ran the company immediately preceding its bail-out.

Thus far, only one former HBOS executive, Peter Cummings, has been punished. In 2012, he was fined £500,000 and banned for life from working again in financial services after being accused of failing to "exercise due skill, care and diligence".

In 2013, the Parliamentary Commission on Banking Standards produced a damning report into the Edinburgh-based HBOS and called on the regulators to look at whether Messrs Crosby, Stevenson and Hornby should also be banned from the industry.

It described Mr Crosby as the "architect of the strategy that set the course for disaster" while Mr Hornby was "unable or unwilling to change course". Lord Stevenson, "who presided over the bank's board from its birth to its death", was said to have been "incapable of facing the realities of what placed the bank in jeopardy".

The joint report by MPs and peers pointed out how as far back as 2004, the Financial Services Authority, the forerunner of the FCA, warned HBOS's growth had so outpaced the bank's ability to control risks that it might have given rise to "an accident waiting to happen".

The FCA report could also throw light on any influence Gordon Brown, the former Prime Minister, might have had in the Lloyds TSB takeover of HBOS in 2009. He is said to have discussed the deal over cocktails with Lloyds chairman Sir Victor Blank in the hours immediately after the Lehman collapse.

The delay in publication of the HBOS report mirrors that of the one being compiled by the Chilcot Inquiry into the Iraq war. It began in November 2009 and concluded in February 2011 but has still not been published more than four years on. Its protracted process has also been put down to Maxwellisation.

In 2008, the taxpayer bailed out HBOS with £20bn injected into Lloyds Banking Group, which took over the mortgage lending giant.

Ian Murray, the Shadow Scottish Secretary, told The Herald the report needed to be published as quickly as possible as there might be significant lessons to be learnt from the whole HBOS saga.

"Given the substantial amount of money that was used to support the banking sector, including HBOS, during the crash, it is in the public interest to have this report published as soon as possible," said the Edinburgh MP.

George Kerevan for the SNP said it was "a matter of public concern" that the FCA had put off publication of its report yet again.