Blackpool Council paid out £9.5m in interest payments on loans in the last two years.
Conservative group leader Coun Tony Williams says the sum is the equivalent of almost £70 for every adult resident of the town.
Today he blasted the ruling Labour authority for its level of borrowing.
He said: “Over the last two years we have paid £9.5m in interest on our borrowings which doesn’t include any additional capital repayment.
“That equates to almost £70 for each adult in the town and this council wants to double its debt by borrowing more which could see our annual interest only payments rocket to more than £8m per year.
“This Labour council is going to put this town into £290m of debt when they have no real business experience whatsoever.
“Our grandchildren’s children will be paying for their recklessness long after they have left the town.”
But council leader Coun Simon Blackburn branded Coun Williams ‘ill-informed.’
He said: “Once again, Coun Williams analysis is ill-informed and completely nonsensical.
“The amount of interest which is payable by the council is directly related to the amount of investment we are making.
“As we borrow money to passport on to local private sector developers, the amount of interest we pay will rise exponentially, but that is a good thing, as we will always collect more in interest payments than we pay out.
“This is about the council making money.”