The full programme relies on £600m being injected into planned schemes from the private sector.
But watchdog MPs on the Environment, Food and Rural Affairs Select Committee have highlighted a growing funding gap because business funding is falling well short of what is expected
Committee chair Anne McIntosh MP said: “The Government has committed £2.3bn in capital funding for six years’ investment aimed at protecting 300,000 properties, but that plan relies on external contributions of £600m.
“We support the principle that the private sector should help to fund new flood defence schemes, but we have repeatedly expressed concern about the relatively small amounts of private sector funding secured to date under the Partnership Funding approach, with only £40m of the £148m secured up to 2014-15 coming from sources beyond local government.
She warned: “It is unclear how the £600m target can be met, and we want Defra to demonstrate how it intends to obtain that money and to explain the impact on its investment programme if the money does not come forward.”