The South Oxhey Initiative has cost more than £600,000 yet "achieved nothing", according to opposition politicians.
Three Rivers figures reveal that the project, which seeks to redevelop the centre of South Oxhey, has cost £629,198 over the last three years.
The district’s Conservative group have criticised the council’s Liberal Democrat administration for going ahead with the project at such a high cost to the taxpayer and with no viable developers on the horizon.
The opposition group’s leader, Ralph Sangster, said: "The Liberal Democrat and Labour groups are not prepared to listen to reason and are now applying Micawber Economics to the South Oxhey project.
"Having spent nearly £630,000 on achieving nothing, they now propose to spend thousands of pounds more on establishing a planning consent for a scheme which in its current form is not financially viable on the basis that something will turn up."
Housing associations, Thrive and Catalyst, have pulled their support for the project, which looks to bring 450 new homes to the estate.
Figures show that £100,223 was spent on "Master Planning", while "property advice" racked up a bill of £279,858 and "legal advice" has set the council back by £162,920.
A further £80,387 was spent on "architectural work" and £5,810 was spent on "other advice".
Leader of the council, Ann Shaw, said the costs incurred from the project so far are essential for the initiative to stand in good stead in the future.
The Liberal Democrat said: "It’s a complex scheme and we’ve had to get proper experience and professional advice from people outside the council. This costs money and when one does this sort of thing we do check that costs are similar to what is going on in other schemes.
"Compare the cost of the South Oxhey Initiative with the Watford Health Campus, for instance, and what we’ve spent in the last three years is equivalent to one year’s costs of the health campus.
"If you don’t get this sort of professional advice when you start, then you pay a much greater cost later on and I think residents are getting good value for money."
Stephen Cox, the district’s Labour group leader, added: "There’s no doubt it is a complex project, but the costs are ratcheting up and there’s been considerable expenditure on this with not much headway. Certainly residents and traders have seen no discernible delivery."
The council expects to submit an outline planning application in June, in the hope that a developer will show interest in the scheme after planning permission has been granted.
Councillor Sangster, representative for Moor Park and Eastbury, said: "The designs at the moment, which has had hundreds of thousands of pounds have been spent on, might not represent a scheme that actually works and putting a planning application in is going to be a cost lot of money on something that may never be built."