Northampton Borough Council has voted to back proposals to create two new unitary authorities.
The scheme will effectively end the existence of NBC and the six other district and borough councils across the county, as well as the cash-strapped county council.
They are now set to be replaced in 2020 by two new unitary authorities representing North Northamptonshire and West Northamptonshire.
Northampton joined the county council, Wellingborough, East Northamptonshire and Kettering in backing the reorganisation so far, with three councils still yet to vote.
It means that the current two-tier system of government, which has been in place since 1974, is almost certainly likely to be replaced by the one-tier unitary authorities, which would provide all services under one roof.
Northampton would be in the West Northamptonshire area alongside Daventry and South Northamptonshire, both of whom vote on Thursday evening.
Northampton Borough Council had initially backed plans for the town to be a unitary authority in its own right, but those plans were essentially scuppered after the government said the area would be too small.
And it was that issue that was at the centre of the debate at The Guidhall this evening.
Resident Arthur Newbury said: "The government gave you one choice. There should have been more banging of the drum to see what government could have done."
But fellow resident Daniel Soan retorted: "There's little desire for the status quo. People are angry and want to see change. Don't be handcuffed to the 1970s. Look forward to a 21st century council. If you vote against this you will be inward looking."
Conservative cabinet member for finance, Councillor Brandon Eldred, said: "There's nothing more I want than a Northampton unitary authority. But financially, we would be bankrupt in a year. It would be a massive gap of £70m per annum, which is an extra £750 per household. That's a massive financial burden on the people of Northampton, and I'm not prepared to do that to them."
Labour councillor Jane Birch responded: "The government has given the people of Northampton no choice. The guidelines preclude anything other than the two unitary proposals. The threat of saying no is being left out of the discussions. It's nothing short of blackmail."
The local government reorganisation proposals were backed by 22 councillors, with 17 against and one abstention.