More homes and businesses will soon be at the mercy of severe weather because a Government boost to flood defence spending is inadequate to deal with the increased risk, MPs have said.
A "major commitment" to enhancing protection announced by George Osborne in last week's spending review was still up to £150 million a year less by 2020 than its own experts said was needed, they warned.
Flood protection was one of the infrastructure investments hailed by the Treasury last week as part of a bid to spur growth, promising £370 million in 2015 and the same in real terms every year to 2020.
Chief Secretary to the Treasury Danny Alexander said it would protect more than 400,000 households.
But in a scathing assessment of the failure to devote sufficient resources to prevent the devastating and deadly floods of recent years, the Commons environment, food and rural affairs committee said that was insufficient.
Last summer Government climate advisers warned of a funding gap of almost £1 billion opening up between what was needed to keep homes and businesses protected from flooding and what was being spent up to 2015,
Environment Agency estimates suggest that by 2020, investment needs to hit £550 million to keep pace with climate and population changes, well short of the latest commitments.
The committee said it welcomed the Government's recognition of the contribution flood defence investment could make to economic growth and regeneration.
"However, funding has not kept pace in recent years with an increased risk of flooding from more frequent severe weather events and the relatively modest additional sums to be provided up to 2020 will not be sufficient to plug the funding gap," it concluded.
It called on Defra to provide "detailed evidence to demonstrate to HM Treasury that flood management capital funding must rise year on year by £20 million over the next 25 years to keep pace with increasing flood threat."