The CIPFA report said it “appears likely that the business case” for creating one authority for Somerset “may have underestimated” how long it would take for the promised financial saving to materialise.
Of the originally promised savings of £18.5m, £8.8m has been achieved to date, with the remainder on track to be achieved by the end by April 2026, as part of the council’s transformation programme.
Mr Fothergill, still a Conservative councillor but now part of the opposition, said the criticisms of the previous council were unfair.
He said: “For six years, in the last 10 years, we have not required that additional council tax take.
“It is a complete fallacy to say that is the root of the problem.
“The root of the problem is the lack of transformation [at the current council] and the lack of transition.”
He said that when he was in charge, he managed to set balanced budgets for six years, while keeping council tax low or frozen.
Mr Fothergill continued: “It’s a fallacy to think that council tax should be increased just to increase reserves, when actually we were going through a period of severe austerity and people needed to have relief on their day-to-day expenses.”
He also disputed the assertion that the timescales for delivering the savings of having one council for Somerset were under-estimated.
The councillor said the Lib Dems did not work fast enough when they took control.