FEWER than one in ten children play regularly in wild places, campaigners warned as they called for new laws to restore wildlife and increase access to nature.

If every household in England had good access to quality green spaces, it could save an estimated £2.1bn in healthcare costs, the RSPB and Wildlife Trusts said.

But the UK's natural environment is in decline, while inactivity and obesity are escalating, towns, villages and cities are facing a growing risk of flooding, and the economy is using the natural world unsustainably, the wildlife groups warned.

The economy, communities, education and well-being are all inextricably linked with a healthy natural environment and people's quality of life will suffer if action is not taken to boost nature, they said.

The RSPB and Wildlife Trusts are calling for a new Nature and Wellbeing Act, which would commit to restoring nature in England within a generation.

New laws would include targets for increasing populations of key species by ten per cent and ensuring that 80 per cent of Sites of Special Scientific Interest (SSSIs) are in good condition by 2040.

The Act would also put a duty on national and local authorities to increase the extent and quality of natural green spaces in all settlements and to ensure all households have access to nature.

A green paper from the conservation groups also calls for the creation of a Natural Capital Committee or Office for Environmental Responsibility to scrutinise new laws for their environmental impact and ensure that nature is properly valued.

The green paper highlights the need for nature, warning that the most deprived communities are 10 times less likely to live in the greenest areas. Fewer than one in ten children play regularly in wild places compared with almost half a generation ago.

The physical fitness of children is declining by up to nine per cent a decade, physical inactivity costs the economy £20bn a year and mental health issues affect one in four people, with the costs of mental health problems soaring to more than £100bn.

But accessible green space is good for mental and physical health, boosting exercise and reducing stress. Nature near home is particularly important for children, helping them cope with stressful life events and increasing cognitive function and attention spans.

However nature is struggling, with 60 per cent of studied species declining in the last 50 years and habitats vanishing.

Campaigner and author Dr Tony Juniper, who is backing the call for a Nature and Wellbeing Act, said: "For too long we've become used to seeing nature as a 'nice to have', a luxury we can afford in the good times. Even worse, we have recently been told that looking after nature gets in the way of growth and competitiveness.

"All this is plain wrong. Nature is neither an optional extra nor a barrier to development. Healthy nature is a vital prerequisite for our long-term health, wealth and security."

Steve Trotter, The Wildlife Trusts' director, England, said: "The green paper provides powerful and irresistible arguments for why we need urgent change.

"If we look after the natural environment, it will look after us and it can help solve some of society's most expensive problems.

"We need new and visionary legislation to underpin the needs of 21st century society in building a better relationship with nature - for people and wildlife."

Martin Harper, conservation director for the RSPB, said: "We know that nature is good for us but we also know that nature is in trouble and that our children rarely play in natural places.

"In this green paper, we demonstrate that our national wealth and our national health depend on action to protect nature, and so do many of our most wonderful species and habitats.

"That's why the RSPB and The Wildlife Trusts are challenging all political parties to introduce a Nature and Wellbeing Act in the next Parliament - only by valuing, protecting and connecting people with our natural world will government achieve its social and economic plans."

Liberal Democrat Environment Minister Dan Rogerson said: "This is the latest welcome step in the RSPB and Wildlife Trust's strong record of campaigning to improve access to good quality natural spaces.

"Liberal Democrats want everyone to have access to nature, which is why we will introduce a Nature Act in the next parliament to improve access to nature and a raft of other measures to build a stronger, greener economy and a fairer, greener society."

A spokeswoman for the Department for Environment, Food and Rural Affairs (Defra) said: "We absolutely recognise how important the natural environment is to people's quality of life.

"That is why we have supported the planting of over eight million trees, invested £88m to improve our rivers - with water quality improving - and established 12 new Nature Improvement Areas to encourage species and habitats to grow.

"We are now expanding England's woodland cover at a rate that hasn't been seen since the 14th century - giving families the opportunity to enjoy the great outdoors."