Flood-stricken communities, including those visited by David Cameron in the Somerset Levels and Yalding in Kent, have been left without planned defences following government funding cuts, the Guardian can reveal.

Undelivered defences, totalling many millions of pounds, also include schemes on the stretch of Devon coast at Dawlish where the mainline railway fell into the sea and near the nuclear power station at Hinkley Point in Somerset.

Ministers have been heavily criticised for cutting flood defence spending by almost £100m a year after taking power, but this is the first time specific projects affected by the cuts have been identified.

In the heart of the Somerset Levels, a £2.2m scheme to improve flood management on the Parrett, the main river draining the Levels, and the nearby Sowy river, was postponed and currently has no prospect of funding before 2020.

In March 2012, an Environment Agency (EA) report on the scheme said: "The [rivers'] combined function is of great importance to the effective management of floodwaters in the area."

Deputy prime minister Nick Clegg is shown around the flooding sites at Burrowbridge, Somerset on February 10. (Ben Birchall/PA)

Another scheme for the Parrett, near the village of Burrowbridge, was in line for £300,000 of funding from 2011-13 but has received nothing. The Parrett overtopped its banks by Burrowbridge in January and the village was cut off.

A third scheme for the river, called "Parrett Estuary – Cannington Bends", worth £6.2m, covered an area near where it meets the sea, just a few miles from the nuclear power station at Hinkley Point.

The defences, which were to be part-funded by Hinkley-owner EDF Energy, would have moved 536 homes out of "the very significant or significant flood probability category to the moderate or low category", according to EA documents. In 2010, the agency said the defences "urgently need updating" and the Cannington Bends area was heavily flooded in 2012, but the scheme has received no funding under the coalition and is currently in line for only £792,000 in 2016-17.

The missing schemes were identified by the Guardian by comparing the flood defence spending plans for 2010-11, the final year of the last government's budget and a high-water mark for flood defence spending, with the plans for subsequent years under the coalition.

Royal Marines from 40 Commando build a sandbag wall in Moorland near Bridgwater on February 7. (Matt Cardy/Getty)

In an interview with the Guardian the under-fire chairman of the Environment Agency, Chris Smith, welcomes the prime minister's recent "money is no object" remark to cope with the fallout of the storms, but wonders whether it will apply beyond the immediate crisis.

"I hope he will apply the same principle to the longer-term issues about improving our flood defences. One of the things that has worried me is whether flood defence is seen by the Treasury as a high enough priority," he says.

Lord Smith says there would have to be an annual £20m rise in the government's £600m flood defence budget, as well as any inflationary increase, just to maintain Britain's present level of protection.

Chris Huhne, the former energy and climate change secretary, claims in a Guardian article that the chancellor, George Osborne, was the driving force behind the cuts in flood defence spending in 2010. The chancellor was then forced to increase flood defence spending last June because insurance companies were threatening to withdraw cover for 350,000 homes at risk, Huhne claims.

Flooding in Yalding, Kent, at the end of January. (Matthew Aslett/Corbis)

Other undelivered flood defence schemes now identified include a project in Devon called the Dawlish Warren and Exmouth Beach Management Scheme, the goal of which was "to reduce tidal flood risk to nearly 3,000 properties and the main railway into the south-west". It had been in line for £2.7m, but by March 2015 will have received only a third of that.

The village of Yalding in Kent began flooding on Christmas Eve, with people evacuated by boat and helicopter, and Cameron was heckled by angry locals during a visit a few days later. It had been in line for £200,000 of flood protection funding between 2011 and 2013, but has received nothing and there is no current plan for spending in the area.

It has also been established that about £5m is being spent between 2011 and 2015 on the Levels to improve the condition of seven sites of special scientific interest where otters, birds and important plants live, as well as to provide more storage for floodwaters. In total, about 1,500 hectares of water-dependent habitat are being improved, thereby avoiding heavy fines under EU environmental directives.

Flood defence funding rose sharply under the last government, following the recommendations of the Pitt review into the catastrophic floods of 2007. Under the coalition, annual spending fell to at least £90m below 2010-11 levels until 2013-14. In July 2012, the Guardian identified 294 flood defence schemes across the whole of England that had been in line for funding but had not gone ahead.

A spokeswoman for the Department for Environment, Food and Rural Affairs, which provides the funding for flood defences, said: "We have spent £2.4bn on flood management and protection from coastal erosion over the past four years. We will continue to build defences where they are needed."

Lord Smith says: "The agency works within clear government guidelines on where to spend the funding it is given to maximise the protection for people and property."

Lord Krebs, the government's lead independent adviser on adapting to the impacts of climate change, said: "Ministers are perfectly entitled to say 'look we just don't have enough money and we will have to accept a greater risk of flooding.' That is a political judgment which needs to be made."

But he said cutting flood defence spending was a false economy, as each scheme saved £8 in damage for every £1 spent: "In the long term these measures pay for themselves."

Krebs warned that without a change of approach to improve flood protection in line with the rising risk from climate change, the current "firefighting" approach to the crisis would be the only one available. "Up to now climate measures have been seen as a long-term issue and it is always difficult for governments to think about long-term issues," he said. "But sometimes it takes a crisis like this to wake people up. Let's deal with the short-term emergency, but I would be very sad if this was all put back in the filing cabinet afterwards."

In his interview, Smith accepts that the EA's response to the flooding has not been perfect. He says it should have pushed harder for the money to dredge the rivers on the Somerset Levels, and he should have visited the county earlier to show support. "There was a whole rest of country to worry about. I was up on the Humber looking at the damage from the storm surge and elsewhere. But I probably should have gone to talk with people down there at an earlier stage."

Smith says more than 5 million people in Britain are at risk of flooding, and that the government has to recognise the dangers. "Flooding knocks out businesses, it knocks out employment, it costs a huge amount to restore. This is something quite apart from the human distress. Government has to give flood defence a higher priority."

Small and medium-sized firms that have been flooded or suffered significant loss of trade will be able to apply for help from the new Business Support Scheme announced by the prime minister. A helpline is also being set up to provide advice.

Cameron said: "The government is taking action across the board to deal with the clear-up and help hard-working people affected by the floods. Dealing with these floods will be a long haul, requiring a stepped-up national effort with the whole country pulling together. We will continue to help the people who need help and protect the communities that need protecting."

The business secretary, Vince Cable, said: "It is vital that small businesses affected by the flooding get assistance as quickly as possible. We know the insurance companies are working to process claims as quickly as possible and we will inform local authorities of their allocations from the Business Support Scheme on Thursday to assist businesses with clean-up costs or help them to continue trading."

Large swaths of Britain remain on high alert, with severe flood warnings still in place along the Thames and in Somerset.

Forecasters predicted some respite this week as largely fine weather with lighter winds and less rain is expected for the next five days.