The Government’s reliance on private investors to support its flood defence building programme has left a £350m gap in the budget, MPs have warned.

As communities in Cumbria begin counting the cost of Storm Desmond, MPs on the Environment, Food and Rural Affairs committee said that the increased risk of extreme weather events would leave flood defence budgets stretched “thinly”.

The Department for Environment, Food and Rural Affairs (Defra) is facing a 15 per cent cuts to its overall resource budget by 2020. Committee chair Neil Parish said that frontline projects like flood defence should be prioritised.

However, he highlighted the committee’s concern that the Government’s six-year, £2.3bn flood defence programme “relies heavily” on private sector investment.

£600m of the flood defence budget is expected to come from sources outside Government, but so far only £250m has been secured, and only £61m from the private sector, the committee’s latest report on Defra performance said.

“We are pleased that the Government is committed to a £2.3 billion programme for flood defences over this Parliament,” said Mr Ship. “But this relies heavily on investment from the private sector, which has not yet been guaranteed.”

A Defra spokesperson said that sources for the outstanding £350m in funding had been “identified”.

Labour’s Shadow Environment Secretary Kerry McCarthy said there was a risk of important flood defence works being “pushed further back towards the end of the six year programme, or abandoned altogether.”

“After year-on-year cuts to flood defence spending during the last Parliament, Defra has cut a further £115 million this year. And yet the risk of flooding is increasing and the need to maintain and build flood defences is greater than ever.

“Defra has been complacent about the risk of flooding for too long, and is failing in its duty to protect vulnerable communities. Securing funding for this vital work must be made a departmental priority,” she said.

The Prime Minister has committed to a review of flood defence spending.

A Defra spokesperson said: “We are investing £2.3bn on new flood defences over the next six years which is a real terms increase on the £1.7bn spent the last Parliament.