Published on the council’s website, external, the report suggested “Birmingham’s current governance, and financial challenges have not been caused by any single issue.”

It said 10 years of funding cuts have caused issues but: “The council’s size, the failure to effectively implement Oracle, its lack of awareness of its equal pay liabilities, and its hosting of the Commonwealth Games are all relevant considerations – but no specific one of these present a root cause of failure.”

Problems with how the council was being run included low levels of trust between staff and elected councillors, a deep-seated blame culture and people working in silos or as individuals rather than one big organisation.

Investigators also reported “a defensive culture where there is difficulty in speaking up about bad news” and said there was also a tendency to try to “minimise bad news”.

Councillors were also found to have restrained officers’ freedom to carry out operational duties by “heavy direction and oversight”.

The council was also accused of having an “optimism bias” with a habit of promising things which could not realistically be delivered.

The report recognised some positive changes have already been introduced but concluded “current actions may not be sufficient to address the significant challenges facing the council.”

Recommendations from the report are due to be signed off by the council’s cabinet on 12 December.