A couple of points about the role of Councils in flooding.
Councils cannot object them selves to houses being built on floodplains, thet is now the Environment agency.
Councils can refuse if the EA objects, but there is now a presumption in favour of Development.
If the application is refused, it goes to the Planning Inspectorate, which is Government not Council.
These appeals are frequently granted and the Councils then have to pay the costs.
These costs can be huge.
Flood Defences are Environment Agency, not Councils.
The amount the EA can spend each year is controlled by Central Government, it is not unlimited.
Any schemes the EA wants have to meet a Cost Benefit Analysis controlled by the Treasury.
The London and South East has much higher property prices, so this is where the money is spent.