Government claims that it is spending more than ever before on flood defences have been labelled "misleading" after figures showed a reduction in funding from the Environment Department.
Updated figures from the Environment Department (Defra) show it is spending £2.34 billion in the current four year spending review period (2011-2015) compared with £2.37 billion spent in the previous four years (2007-2011).
Defra said spending was at record levels, once "partnership funding", in which developers, businesses, local authorities and communities contribute towards paying for flood defences, was taken into account.
The department said it expected some £148 million to be delivered from non-Government sources over the current spending review period.
But environmental campaigners said ministers had misled Parliament and the public by claiming the Government was spending more on flood defences.
Environment Secretary Owen Paterson has claimed: "This Government is spending more on flood defences than any previous government."
And Prime Minister David Cameron told the Commons earlier this month: "In this current four year period, we are spending £2.3 billion, compared with £2.1 billion in the previous period."
It later emerged that the PM's figure of £2.3 billion was for the period 2010/11-2013/14, which includes the final year of the last Labour government's financial commitments, when spending reached a high of £670 million, and the £2.1 billion was for 2006/7-2009/10.
Friends of the Earth climate campaigner Guy Shrubsole said: "Owen Paterson's own department has now been forced to admit it has cut flood defence spending, despite claims to the contrary by the beleaguered Environment Secretary.
"On the basis of these figures, it appears both Mr Paterson and the Prime Minister have misled Parliament and the public.
"They must apologise, but most of all they need to get serious about defending the country from increasing flooding as climate change worsens.
"This means greater investment in flood defences and reversing damaging cuts to the Environment Agency.
"It also means halting their reckless pursuit of shale gas, which will increase climate change and make flooding worse."
Shadow environment secretary Maria Eagle said: " It is humiliating for David Cameron and Owen Paterson that they have finally been forced to reveal that spending on flood protection was not protected when cuts to the Environment Department's budget were made.
"The Prime Minister must now stop repeating his misleading claim that more is being spent in the current four year period than in the previous four years, when these new figures reveal that is simply not true.
"The Government should also stop including money that they hope to attract from external contributions but have so far failed to secure."
A spokeswoman for Defra said: "We are spending £2.3 billion on flood defences and along with partnership funding this is more than ever before.
"We have also committed to record levels of future capital investment, at £370 million for 2015/16 then rising to over £400 million in 2020/21.
"In addition we have provided the Environment Agency with an above-inflation increase of £5 million on their floods maintenance work in 2015/16."
In real terms, once inflation has been taken into account, capital spending on flood defences will have fallen from record spending of £371 million in 2010/2011 to £336 million in 2015/16, and will remain at the same level until 2020/21, according figures supplied by Defra in response to a written question by Labour.
The Environment Agency has said it needs a £20 million year on year increase on top of inflation in order to keep pace with the increased risk of flooding in the face of climate change.
Defra said that £35 million from non-government sources had been spent on flood defences so far, and that the rest of the £148 million had been committed and would be spent by the end of the spending review period.