A scramble for cheap homes led to developers building on land they knew could fall victim to flash floods.
The Environment Agency said experts were ignored as the local authority clamoured for extra housing in Kidlington - a 'calculated risk' that deepened the chaos over Easter.
At least 350 people were evacuated from houses built in the 1950s and 1960s when the River Cherwell burst its banks. In Banbury, Spiceball Leisure Park - built by the river in the 1980s - was also flooded out.
Now Peter Borrows, the Environment Agency's Flood Defence Manager, has rounded on planners who let such risky projects get the go-ahead.
He said: "They did listen but they chose to disregard the advice. Things have changed since then.
"Spiceball was built right by the river, within a few yards of the Cherwell. "Clearly the events which occurred at Easter were very much more significant, and levels of water at Spiceball a metre higher, than anything in the past.
"At the time planners were aware of the flood risk but they took a calculated risk that did not pay off."
In Kidlington properties built by the river fell victim to the tidal wave that swept from the north.
Mr Borrows said: "The pressure was to build and land was cheaper in the flood plain.
"It is less desirable land, but it is flat and easy to build on.
"People did not take the risk into account in those days. We are getting wiser although we are not fully there at the moment.
"You can never actually eliminate flood risk but you can reduce it." Damage caused by the floods - described as the worst for 50 years - was made even worse because the Environment Agency made crucial errors.
In a independent report published yesterday(THURS), it was accused of giving most homes in Kidlington no prior warning.
Misunderstandings between the agency and emergency services, such as the meaning of warning codes, also slowed the rescue effort. The review team made a host of recommendations to avoid a repeat of the chaos, which the agency has pledged to enforce despite a lack of funds.
Later this month, it will meet residents and councillors in Kidlington to discuss putting an early flood warning system in place.
The report also revealed that the A34 and A40 roads, which cut below the village, helped deepen the crisis.
The roads, built above general flood plain levels, trapped the flood water and increased its height.
Evan Harris, MP for Oxford West and Abingdon, said the roads acted as a 'huge dam'. He added extra cash must be found to meet the multi-million pound cost of improvements. "These remedial measures are going to cost money and the Government will say that other Environment Agency priorities will have to be cut."
Meanwhile, the agency has stamped on conspiracy theorists who believed Kidlington was 'sacrificed' to save Oxford.
Mr Borrows said: "When you have got flooding to that extent you cannot control it.
"We never sacrificed anywhere for another town. It is not possible to flood places to save others."
Converted for the new archive on 30 June 2000. Some images and formatting may have been lost in the conversion.
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