Wildlife groups in the Westcountry say the pursuit of an economic agenda based on the "mythical notion" that growth and the protection of nature are mutually exclusive has derailed the Government's plan to be the "greenest ever".
Conservationists in the region were responding to an annual audit of the Coalition's pledges on wildlife and the countryside, which found that nine out of 25 key environmental commitments were not being met, while good progress had been made on just four.
The damning report published yesterday by Wildlife and Countryside Link, a group of 41 charities, has concluded that ministerial decisions are "more likely to harm nature than to support it".
The study has raised serious concerns about the impact of controversial planning reforms on green-belt land and Sites of Special Scientific Interest, warning that protections for such areas are "uncertain" and do not appear to be a priority.
It also criticises the controversial badger cull for failing to be balanced or science-led, claiming it is a "costly distraction from the development of a more rigorous, effective and publicly acceptable" way of controlling the spread of bovine tuberculosis.
There has also been no progress on farm animal welfare, designation of a full network of Marine Conservation Zones or halting declines in wildlife, according to the annual Nature Check report.
Harry Barton, chief executive of Devon Wildlife Trust, said the Government was not failing in every area, but the general direction of travel was "backwards".
"They really need to get away from the idea that protecting and looking after the environment is getting in the way of economic growth, as there is no evidence to support this," he added.
"There is a sort of framework of values which is saying that Britain's place in the world is about growing as fast as possible and that we have got to take away any constraints. The value of tourism is linked to the landscape and to say that [protecting the environment] is an obstacle to economic growth is very short-sighted and blinkered."
The report uses a traffic light system and gave the Government a green light for its action on ash dieback, which has ravaged ash populations across Europe and has been found in some sites in the South West.
Work on the Common Fisheries Policy, which has led to improved fish stocks, and international work to protect elephants, rhinos and whales have also made good progress, it said.
Tony Whitehead, spokesman for the RSPB in the South West, said the region was one of the best places for wildlife in the UK and home to a passionate group of campaigning nature lovers.
He added: "This is why it is so disappointing to read that the Government is failing to deliver nearly a third of its natural environment commitments.
"Because in failing the environment they fail everyone in the Westcountry who wants this precious part of the world to be the very best it can.
"Sadly though, wildlife NGOs with public support are having to spend a lot of time arguing against policies based on a mythical notion that economic growth and protection of the environment are mutually exclusive. We need to move quickly beyond this myth, especially here in the Westcountry, where the quality of our environment underpins our economy and our sense of well being."
Environment Secretary Owen Paterson conceded that the Government may have "gone backwards" in some areas, but said the report was a subjective and unfair opinion by groups including fierce critics of the ongoing badger cull.
He dismissed the suggestion that economic growth and green policies were mutually exclusive.
"They are being unfair. A lot of this is just an expression of opinion," he told the BBC Radio 4 Today programme.
"These are very active campaigning groups, we have vigorous discussions with them on many issues. On this, a lot of their conclusions are very subjective and I think they are being pretty unfair."
He went on: "I'm pleased they gave us a 'green' on some. I would dispute some of the 'ambers' where I think they are really being very hard and negative on us and I would disagree with some of the 'reds'.
"The environment is such a huge, vast, all-encompassing tableau. There are areas where we will have gone backwards, there are areas where we will have advanced."