After the floods, a new storm is gathering over Westminster

As summer approaches, thousands of Britons are marking the gloomy first anniversary of events that wrecked their lives – and shook the UK's insurance industry to its core.

The most recent government figures show that more than 5,000 people are still unable to return to their homes, with around 1,400 living in caravans, as a result of last year's wet weather and the subsequent floods that ravaged large parts of the country.

Those floods cost the insurers £3bn – the biggest single natural disaster yet seen in the UK, at least as far as insurance losses are concerned. To put it into context, that £3bn is equivalent to the cost of rebuilding Wembley Stadium four times over. It is not a loss insurers want to take again.

The Association of British Insurers (ABI) will next week hold a conference in Westminster to discuss the action the Government has taken to mitigate the impact of the further floods predicted within the next few years as climate change takes hold.

Senior figures in the industry have a stark message for ministers: "You're not doing enough. You're not even close."

An agreement was reached between the Government and insurers, the much-vaunted "statement of principles", pledging that 2.2 million people in high-risk areas would continue to receive cover (at market rates). This still holds – in theory – but in February it was put up for review. And there is evidence that, on the ground, it is under strain.

Eamonn Flanagan, insurance analyst at investment bank Shore Capital, says: "The increases [in premiums generally] have not been anywhere near as high as expected. So what we think is happening is that in flood-affected areas companies are still willing to offer quotes, but those quotes are either too high for people to afford or they come with exclusions."

Insurers argue that the Government has not fulfilled its side of the bargain by improving flood defences. At the conference, Nick Starling, director of general insurance and health at the ABI, will have some hard words for ministers. As he says: "There are only so many £3bn hits you can take."

If action is not forthcoming, some people in flood-risk areas could find themselves unable to get insurance at any price.

"We need the Government to have a clear strategy for reducing flood risk," continues Mr Starling. "They have done things such as strengthening the planning guidelines, but there are still developments getting through that shouldn't be. If they want to build in those areas then buildings should be designed to take account of the risk."

Norwich Union, Britain's biggest insurer, paid out to more than 45,000 households and 6,000 businesses as a result of last summer's floods. It expects its final bill to come in at £475m.

"To that end I think we and the industry have performed well," says Dominic Clayden, NU's director of claims. However, he adds: "We cannot escape the fact that the type of flooding we saw last summer is likely to become more frequent in the future, and insurers need assurances from Government that it is going to manage flood risk well enough so that we can continue to insure properties on a commercial basis and at an affordable rate for customers."

He adds: "We need to know which homes will get flood defences and when, and which ones won't. We also want to know what the Government's plans are for the homes they don't think can be defended cost effectively, and for tackling urban drainage and surface water flooding [from which the majority of last summer's claims hailed]. We need a Floods Bill [as the Government has recently announced] to clarify responsibilities for the many different bodies involved, to ensure that a co-ordinated approach is adopted."

The ABI certainly supports the call by the Environment Agency to be given overall responsibility for dealing with the issue. The agency's chief executive, Paul Leinster, said last week: "It's clear that urgent action is still needed. We believe that the Environment Agency in England should be given a strategic overview role for all types of flood risk – and when given clarity on this role and the role that local authorities will play, we can begin to advise on priorities for action."

The ABI conference is likely to coincide with the final publication of the government-sponsored report into last year's floods, being prepared by Sir Michael Pitt, chairman of the South West Strategic Health Authority. His interim report called for floods to be taken more seriously than in the past, and made 15 "urgent recommendations".

With Treasury coffers nearly empty and a recession brewing, ministers have little room for manoeuvre and might resist demands from the insurance industry to splash the cash on fighting floods.

But if action isn't taken, the industry position is clear: "We bailed you out once. We're not going to do it a second time."