The government’s underlying spending on flood prevention has been cut with only half the country’s defences being sufficiently maintained, a new report is warning.

The National Audit Office (NAO) said funding on food protection has fallen by 6% in real terms between 2010/11 and 1021/15, despite an extra £270m being awarded following the winter storms of last year.

The report said that while the Environment Agency has improved the way it prioritises flood risk spending, it still has ‘insufficient’ funding to maintain defences.

Amyas Morse, head of the National Audit Office, said the agency was providing value for money but added: ‘If we set aside the emergency spending in response to last year’s floods, and give due credit for efficiency improvements, the underlying spending on flood defences has gone down.

‘The Agency, as it recognizes, will need to make difficult decisions about whether to continue maintaining assets in some areas or let them lapse, increasing in future both the risk of floods and the potential need for more expensive ad hoc emergency solutions.’

However, the Government disputed the funding claims saying the report used ‘inappropriate comparisons’ and flood spending had actually increased by 5% in real-terms.

Flooding minister Dan Rogerson said: ‘The NAO has drawn conclusions on funding based on inappropriate comparisons. We have invested £3.2bn in flood management and defences over the course of this parliament which is a real term increase and half a billion more than in the previous parliament. This has allowed us to protect 165,000 families and households in vulnerable areas.’