MPs have been advised that a 500-page report into the collapse of Scottish bank HBOS has been delayed, possibly delaying it being published until 2016.

The authors of the report, which was commissioned in 2012, are still working to “ensure that its contents are fair and balanced and accurately represent all the facts”, according to a letter from the FCA and the Prudential Regulation Authority.

The delays relate to the process of Maxwellisation, in which individuals who are criticised in the report are approached to exercise their right to reply.

The letter, sent by PRA chief executive Andrew Bailey and the FCA’s Sir Brian Pomeroy to the House of Commons Treasury Committee, says the authors have been “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 process will begin “in the coming weeks” but the letter says it is “difficult to estimate in advance” how long it will take, because the authors will still need to obtain consent to publish “confidential information” in the report after completion.

The letter adds: “We are therefore not yet in a position to provide precise timing on the publication of the report.”

However, the delay makes it unlikely that the report will be published before 2016.

Andrew Tyrie, who chairs the Treasury committee, told the Financial Times: “We have been waiting a long time. The review should be published as soon as possible.

“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.”