Flood defence spending was £2.37bn between 2007 and 2011, according to House of Commons library figures.
Between 2011 and 2015 it will be £2.34bn - a £247m cut in real terms.
It comes after the Prime Minister said his government was spending more on flooding than any previous administration.
Friends of the Earth (FOTE) called on the Government to ‘close the gaping hole in UK flood defence spending and do more to tackle climate change’.
FOTE campaigner Guy Shrubsole said: “This confirms what we have been saying all along: Government spending on flood defences has fallen.
“Tens of thousands of homes are currently at risk from flooding - and many more will be threatened as climate change takes hold.
“Ministers must stop spinning the figures and take urgent action. The yawning hole in flood defence spending must be closed – and slashing the nation’s carbon emissions must become a top priority.”