Maghull Town Council's leader said the Labour administration was on a mission to bring openness and transparency to the council after uncovering a "veil of secrecy" around the town hall roof rebuild.
Cllr Caroline Esterson said the Labour Councillors' investigation into the expensive project had been "frustrating" because of the lack of clear procedures and book-keeping.
What the investigation did uncover was that the previous Lib Dem administration signed off on the work just hours before losing control of the town council last year.
This saddled Maghull's tax payers with hundreds of thousands of pounds worth of debt.
Even the exact cost of the work was difficult to get to the bottom of, the town council leader said.
Cllr Esterson said: "The catalogue of failings behind this project was appalling. The Labour Councillors on the town council immediately launched an investigation into the scheme as soon as we got into the town hall last year.
"Because proper procedures hadn't been followed by the Liberal Democrats, it was extremely difficult to even get to the bottom of some of the most basic facts, such as how much would the work cost the tax payer of Maghull.
"There appeared to be this veil of secrecy over the whole scheme.
"So we went as far as we could and we handed our findings to independent auditors from Sefton, who carried out their own investigation. The police asked for the auditors' report, so they could look into the findings.
"What the audit report shows, is that there was a catalogue of mismanagement by the Liberal Democrats.
"The report found substantial and systematic failures in procurement practice and lack of transparency in the process.
"Auditors also found no evidence had been unearthed to show that the construction of the roof needed to have taken place at all.
"They also found that there was no evidence to show that simple repairs to the roof rather than a new roof would have sufficed.
"In addition to significant failures in the process there were also fundamental breaches of financial regulations and standing orders by the town council itself throughout the period before Labour took control.
"And there had been a lack of evidence to demonstrate value for money."
Cllr Esterson said while measures were being taken to ensure that all decisions by the council are now taken in a fully open and transparent manner, the previous Liberal Democrat councillors must accept responsibility for the "roof fiasco".
Cllr Esterson said: "We have introduced measures to ensure that nothing like this can happen in the future.
"Once the Labour Councillors took control last year, we set about ensuring that the town council was fully transparent.
"That's why we have fully reviewed council procedures to ensure this can never happen again. The people of Maghull need to be able to see how their money is being spent and if it is being spent wisely.
"This is something which the previous Liberal Democrat administration systematically failed to do but they have a responsibility to answer the questions which the people of Maghull are asking.
"So Maghull Town Council has again formally asked the Lib Dems on the council to finally explain why they made the decisions they did."