The UK's natural resources have been valued for the first time as being worth almost £19 billion a year.

The figure comes in a National Ecosystem Assessment (NEA), which was commissioned by ministers to try and put a figure on nature's value to the economy as a way of helping to shape urban and rural planning policy. The UK is the first nation to produce such a detailed assessment.

Currently, only material products such as foods are given a value in the economy, but conservation organisations are hoping that this will change now.

The findings are anticipated to influence the content of the eagerly awaited Natural Environment White Paper, which was promised this spring.

Nature's economic benefits manifest themselves in food production, health and general well-being.

Although it has long been known that living near to greenspace promotes health and increases the value of a property, the report puts a value on this as up to £300 per person per year in health benefits.

"The natural world is vital to our existence, providing us with essentials such as food, water and clean air - but also cultural and health benefits not always fully appreciated because we get them for free," said environment secretary Caroline Spelman.

A good example of the close relationship between nature and the economy is that the diseases currently affecting honeybees - Colony Collapse Disorder and Varroa - have an immediate effect on food production.

Less obvious connections include the health of soil, hedgerows, waterways and coastlines on production and pollution.

"Humans rely on the way ecosystems services control our climate - pollution, water quality, pollination - and we're finding out that many of these regulating services are degrading," said Bob Watson, chief scientific adviser to Defra and co-chairman of the NEA.

"This report is saying 'this has got incredible value, so before you start converting green space into building, think through what the economic value is of maintaining that green space' - or the blue space: the ponds and the rivers.

"About 30% of the key ecosystem services that we rely on are degrading. But about 20% are getting better - our air quality has improved a lot - and what this report says is that we can do a lot better across the board," he said.

Another of the report’s 200 authors, Ian Bateman, an economist from the University of East Anglia, qualified it by saying that putting a single price on nature overall was not actually sensible.

"Without the environment, we're all dead - so the total value is infinite," he observed wryly. "What is important is the value of feasible, policy-relevant changes - and those you can put numbers on."

The 2,000-page report is truly exemplary in its academic rigour and thoroughness. 27 main chapters, and 11 supporting chapters for the economics sections, cover every aspect from mountains, moorlands and heaths to the cultural services of nature that we take for granted.

They take in the different regions of the UK as well as our dependence on ecosystems outside of the UK.

Attempts to put a value on every single aspect of this are made, with reference to hundreds of other studies.

Pollinating insects are calculated to contribute £430 million to the economy, while inland wetlands are valued at £1.5 billion – a high figure because they help to produce clean water.

Other aspects of the evaluation are less precise because the costs and benefits are harder to quantify, and may change over time.

The report does contain many examples of successful interventions, and sustainable ways in which communities are living with nature.

It emphasises the importance of sensitivity to spatial and temporal scale – that ecosystems cross administrative boundaries and work over timescales. It therefore calls for "institutional mechanisms that link across scales, provide opportunities for stakeholder engagement and collaboration between actors"- which might be taken as a coded comment on the government's controversial abolition of regional bodies.

The report concludes that the UK’s ecosystems are currently delivering some services well, but others - about 30% - are still in long-term decline. This includes soil quality and species diversity.

The UK population will continue to grow by nearly ten million in the next 20 years, and its demands and expectations continue to evolve. This is likely to increase pressures on ecosystem services in a future where climate change will have an accelerating impact both here and in the world at large.

The public and all organisations are invited to respond to the report which is likely to have a huge influence on future policy.