Business leaders, investors and campaigners have delivered a thumbs down to the government's record on green issues, less than a year after David Cameron announced his aspiration to lead "the greenest government ever".

One investor said the coalition's actions threatened to "choke off the lifeblood of the green economy" and another said he was "bitterly disappointed" by the coalition's performance.

Penny Shepherd, chief executive of UKSIF, the UK's leading organisation representing financiers specialising in green investments, warned that the chancellor, George Osborne, had not lived up to his promise of "greening" the Treasury.

"Until the Treasury is firmly and visibly behind the low carbon transition, and the shift to a green economy and green financial services, then the rest of government will inevitably struggle," she said.

The comments – after a series of U-turns and watered-down or delayed green policies – come as the government braces itself for a report next week from the CBI which is expected to criticise its record on supporting green business.

Five years ago this week, Cameron's photogenic husky ride across the snowy Norwegian island of Spitzbergen was intended to give voters a glimpse of a different kind of Tory leader and was part of his strategy of detoxifying the brand. And just three days after forming the coalition he declared that he would be the "fourth minister" at the Department of Energy and Climate Change, adding: "I mean that from the bottom of my heart."

In that speech he said that the government would back green industries to drive economic growth, adding that the UK needed to "make sure we have our share of the industries of the future".

Now, though, many of the business leaders and investors whom the government is relying on to deliver that growth are becoming increasingly frustrated.

Mark Shorrock, founder of Low Carbon Group, which invests in solar, tidal and wind power, said: "The government has been shortsighted on green issues, and is threatening to choke off the lifeblood of the green economy."

Green entrepreneurs were also critical. Jeremy Leggett, founder of Solarcentury, said: "I am bitterly disappointed. I was impressed by the promise to be the greenest government ever. The coalition could have created a really convincing narrative of genuine job creation but they have failed to do so."

Shepherd said: "One area of particular concern has been the changes to feed-in tariffs [subsidies for renewable energy]. It wasn't the proposal itself, but the sudden revision that sent out the wrong signal – investors need confidence that policy will remain stable."

A recent report from respected US thinktank the Pew Environment Group appears to bear out these views. From being third in the world in green investment, the UK has tumbled to 13th place, well behind developing countries such as China, India and Brazil in the race to create green jobs and become a leader in green technology. Last year, only £2bn was invested in alternative energy and clean technology in the UK, compared with £7bn in 2009. Germany spent £26bn and the US £21bn last year.

Jonathon Porritt, whose Sustainable Development Commission was axed within months of the coalition coming to power, described government performance on green issues as "really thin".

"All the possible good things are in the future. If you have to rely on [the Natural environment] white paper as an example of what is good, that's pretty desperate. What is a white paper - just paper," he said.

The coalition's own MPs have also expressed concern on key policies. Tim Yeo, the Conservative former minister and chair of the cross-party environmental audit committee, said: "They are making progress but there is a very long way to go. The changes to feed-in tariffs unsettled investors, undoubtedly. I think David Cameron remains committed, but there is a lot of sucking and seeing to do."

But the government strongly rejected the criticism. One Whitehall insider said: "Investors are reacting positively and recognise we're acting for the long term." He pointed to a survey of more than 300 UK clean technology companies, from the government-funded Carbon Trust, that found increasing confidence about their growth prospects, with more than three-quarters looking to recruit in the next 12 months and 37% planning to expand into new export markets in the next two years.

Benj Sykes, director of innovations at the Carbon Trust, said: "Our research shows that cleantech innovators are feeling optimistic about their prospects and have ambitious plans for the future. However, access to finance, along with a stable policy environment, will make or break these growth prospects."

Bob Wigley, the ex-investment banker and chairman of Yell, who drew up the blueprint for the green investment bank, told the Guardian that even in its watered down form it was a significant achievement: "I think the chancellor deserves credit for finding £3bn during this challenging period of austerity to fund a green investment bank. I guess we all look forward to hearing the detail of its mandate. But assuming the right mandate, funding and governance structure, it could be one of the coalition's really substantive legacies, and another world-leading project that other countries will want to emulate."

Renewable UK, the trade body for the wind industry, also said it was "encouraged" by the government's support for offshore wind. "We are hoping that the positive commitments that have been made are followed up with the right level of financial support," a spokesman.

His views have been echoed in a series of reports from parliamentary committees, which have criticised the government over the green investment bank, flood defences and air pollution.