Almost 10,000 new homes could be built on some of the most flood-prone areas of England, a Greenpeace investigation has found.
They include hundreds of new-builds in Sheffield and Doncaster, the towns hit hardest by the latest floods.
The Environment Agency told the BBC that virtually all planning applications last year followed its advice on flood risk.
But it predicts the flooding risk will increase because of climate change.
The Greenpeace study comes as hundreds of flood-hit homes in South Yorkshire and Derbyshire are still evacuated.
It identifies plans to build a total of 9,688 new homes in high-risk areas.
More than 5,000 homes have been proposed in high-risk zones of Lincolnshire, where roads and thousands of acres of farmland have been flooded in the last few days.
The developments include Boston United Football Club's new 5,000-seater stadium.
The research also highlighted a 3,100-home "new town" near Stainforth, less than two miles from Fishlake, the village where hundreds of people have been forced from their homes because of flooding.
The project includes what has been described by developers as a "marina".
These properties have not yet received full planning permission but have been ear-marked by the local authority for development.
The Greenpeace study selected the 10 English councils with the highest percentage of land covered by high-risk areas using the Environment Agency's map.
It then plotted these against sites that the councils listed in their five-year plans for housing supply.
Sheffield and Doncaster were added after the recent flooding in those areas.
The work found that, as well as hundreds of new homes in high-risk areas of these towns, thousands of homes are planned for medium-risk zones.
The Environment Agency defines a high-risk flood zone as one where there is a one in 100 chance of flooding in any given year.
Medium-risk zones are areas where there is a one in 1,000 risk of flooding in any year.
'Planning for disaster'
Greenpeace's chief scientist, Doug Parr, described the plans to build homes in areas at high risk of flooding as "literally planning for disaster".
"Flooding has been flashing on the radar as one of the major impacts of the climate emergency in the UK for years," he said, "yet our planning system keeps failing to properly recognise it".
The Environment Agency told the BBC that local planning authorities are responsible for approving proposals for new development in their areas.
However, it said the National Planning Policy Framework makes clear that inappropriate development in areas at risk of flooding should be avoided.
"In some places it will be challenging to avoid these areas," the Environment Agency statement said, "due to limited land outside the flood plain or because of other sustainable development objectives."
Nevertheless, the agency claimed that, between 2017 and 2018, 99.4% of planning applications involving new homes were decided in line with its advice on flood risk.
The Local Government Association told the BBC that the figure for 2018-19 was a bit lower, at around 97.3% .