Government-appointed commissioners have criticised the decision not issue a report into the financial collapse of a county council.
Tony McArdle and Brian Roberts came in to oversee Northamptonshire County Council in 2018.
The authority, which is due to be scrapped, ran out of money after years of financial mismanagement.
In a letter to the government the pair said they were "surprised" and "disappointed" by the decision.
It was hoped that a public interest report would give a definitive official account of why the authority failed to balance its books.
But the council's previous auditors KPMG have decided against the move, according to the Local Democracy Reporting Service.
KPMG have been approached for comment.
In a letter to the Local Government Minster Robert Jenrick, Mr McArdle and Mr Robert said: "For the first local authority in a generation to effectively declare itself insolvent not to be the subject of such a report is certainly surprising.
"We are disappointed by this decision. We believe there is a lot to learn from Northamptonshire."
The commissioners also said the authority's finances "remains considerably weaker than other county councils" despite recent improvements.
Northamptonshire County Council's money problems led to a scheme to scrap it, along with seven other district and borough councils, in 2021.
A draft Structural Change Order confirmed two "shadow authorities" would be set up during a transition period.
Existing councils will be scrapped and replaced by two unitary authorities, West and North Northamptonshire.
But due to the coronavirus pandemic, elections to the shadow authorities have been postponed.