THE official report into the collapse of HBOS is unlikely to be published this year – more than seven years after the taxpayer bailed out the Scottish bank to the tune of £21 billion, it has emerged.

A letter to the Commons Treasury Committee from those overseeing the report refers to the so-called Maxwellisation process – whereby anyone criticised in it has a right to reply – and reveals how there have been over 1400 representations from more than 35 different individuals or their legal representatives.

The review itself has involved more than 240,000 electronic documents and in excess of 80 interviews of relevant individuals.

While the 500-page report is in draft form, work is “continuing to ensure that its contents are fair and balanced and accurately represent all the facts”.

However, the letter to the committee, from Andrew Bailey of the Prudential Regulation Authority and Sir Brian Pomeroy of the Financial Conduct Authority, says that having completed the “first wave” of Maxwellisation, analysis has led onto another stage: a “re-Maxwellisation process”.

“We are required to re-Maxwellise anybody in relation to whom, as a result of changes made to the Report, we consider the level of criticism to have increased,” the letter explains.

This new process will begin “in the coming weeks” but once it has been completed, consent from those involved will be needed to publish any confidential information covered by the 2000 Financial Services and Markets Act.

The letter says it is "difficult to estimate in advance" how long the re-Maxwellisation process will take and adds: "We are therefore not yet in position to provide precise timing on the publication of the Report. We can assure you that we remain committed, as ever, to publishing the report as soon as is practicable.”

In June, The Herald reported how the report into the collapse of HBOS had been further delayed until the autumn at the earliest; the re-Maxwellisation process could now delay publication until 2016.

Andrew Tyrie, the Committee Chairman, calling for the report to be published as soon as possible, said: “Once the review has concluded, I will be asking the Treasury Committee’s independent reviewers to give the Committee their views on the reasonableness or otherwise of these delays in the process.”