An official probe by Isle of Wight Council last week confirmed that consultancy work on an £18M road scheme on the island was illegally procured.
The investigation by solicitors Wragge & Co found that consultancy work was awarded illegally to consultant High Point Rendell following a landslip along the A3055 Undercliffe Drive 2001.
The award was made in contravention of European Union procurement law because the contract was not put out to tender.
Failings in the "individual performance of officers" and in the council's contract procurement procedures are detailed in the investigation's final report, published last Friday.
Isle of Wight Council chief executive Joe Duckworth this week pledged to act on the findings.
"The report makes uncomfortable reading in that it highlights widespread and systematic failings in the council's systems," he said.
"It is crucial that we now learn the lessons from this unfortunate episode. These recommendations will now be carefully studied and implemented where necessary."
Duckworth added that the council last week approved a new procurement and contracts code.
Officers involved in the procurement including regeneration and development director Derek Rowell and deputy chief executive John Lawson have since left the council.
In total seven Isle of Wight council officers were suspended over the irregularities. One retired early, two were sacked, two resigned and two have since returned to work.
Isle of Wight also last month scrapped the £18M scheme to upgrade Undercliffe Drive and stabilise the slopes overlooking the road.
Instead it will go for the cheaper option of upgrading a road through nearby Whitwell.