A councillor has warned that plans to regenerate a New Town's centre should be viewed with caution until finance for the £1bn plan is certain.
Liberal Democrat Robin Parker said several "grandiose" schemes to revamp Stevenage have failed in the past.
"A project like this is never secure until you have got the money," he said.
Labour's John Gardner said £350m had been pledged by the private sector for phase one of the project - known as SG1.
Stevenage was designated a New Town in 1946 when its population was about 6,000 and it had grown to 84,000 by the time of the 2011 census.
The current plan, which does not yet have planning permission, includes thousands of new homes, with bars, shops and leisure facilities, such as a skating rink or ferris wheel.
Plans for the first phase include a new council office, health centre, library and 1,239 homes.
"There have been three or four misfired schemes over the years - and every time the money has fallen through," said Mr Parker.
He had reservations about SG1 because it relied on private investment and he feared uncertainty in the property and retail markets.
Labour council leader Sharon Taylor said: "The major part of the development is making sure we've got more bars, cafes, leisure uses as well as residential and flexible co-working space to drive the footfall to support some of the retail.
"We've already got about half a billion pounds worth of investment, most of it being private money, I have no concerns about funding for that development now."
Paul Mackulin, who runs a pie and mash stall at the indoor market, said people were "sick and tired" of waiting for the regeneration.
"But if it does go ahead, it will put us back on the map and be good for the local community," he said.
Mr Gardner, who is responsible for regeneration, said Stevenage would become "a town centre to be proud of".
He said funds for the first phase had come from Mace, the council's development partner, and the Hertfordshire Local Enterprise Partnership.
"This shows the confidence of the private sector which sees Stevenage as a destination town," he added.
Watch a report on SG1 on Sunday Politics East - broadcast on BBC One on 6 October.