Yesterday WWF hosted an event in the margins of the Clean Energy Ministerial meeting in London, where we heard from Environment Ministries in Germany, Denmark and the UK about the importance they attach to developing renewable energy industries - for their economies, as much as for the environment.

On a day when Foreign Secretary William Hague and Energy Minister Greg Barker and both showed leadership on the need to tackle climate change through investment in clean energy sources, David Cameron remained conspicuously absent from the debate.

Six years ago, almost to the day, WWF took David Cameron on a trip to Svalbard in the Arctic. The trip, which included a visit to the Scott Turner glacier, was to be a turning point for Cameron and the Conservative party.

Pictures of him hugging a husky appeared in most British newspapers and the electorate saw it as a symbolic moment in the 'detoxification' of the party's brand. The message was clear: the Conservatives had changed; they were no longer the 'nasty party', and a deep commitment to tackling environmental problems was part of the package.

Back home, David Cameron also debunked the idea that environmentalism was a luxury that can be disposed of when the economic going gets tough, boldly stating that, "the truth is: it's not that we can't afford to go green - it's that we can't afford not to go green."

Now fast forward six years; David Cameron has been in Downing Street for nearly two years and the news that he was to deliver his first major speech on the environment as prime minister, at the third Clean Energy Ministerial (CEM) in London this week, had had the green sector buzzing with speculation.

But then, the rumours started circulating on Monday night that plans for a speech by Cameron had been scrapped, or at best 'downgraded' to a simple Q&A with ministers attending the CEM.

The news prompted howls of dismay from both environmentalists and those businesses investing in renewables and the green economy alike. The CEM throws a spotlight on the government's record on tackling climate change and promoting renewable energy in the UK - a record that worries me.

At a time when we are seeing increasing disarray in the government's climate and energy policies on both domestic and European policy areas, it seems clear that the prime minister is struggling to co-ordinate his ministers, party and MEPs on these issues.

The mere fact that he hasn't made any major speech on the environment yet, and has largely refrained from intervening in what is becoming an increasingly negative debate among members of the cabinet and his back benches, has inevitably led many to question David Cameron's personal commitment to lead the "greenest government ever."

On clean renewable sources specifically, some parts of the government have given out mixed messages, with the result that investor confidence has been seriously weakened. This is in stark contrast to other countries, such as Denmark and Germany, where a strong policy framework and consistent political signals have encouraged inward investment and hundreds of thousands of jobs.

Investor confidence has, for example, been hit by the bungled move to reduce solar feed-in tariffs (FiTs); whilst we agree that tariffs should fall in line with technology cost reductions, the short-notice cuts to solar FiTs hit businesses hard and resulted in a judicial review that the Government lost.

Elsewhere, a letter to the prime minister from over one hundred, almost exclusively Conservative, backbenchers attacking wind power, and recent comments by DECC minister Greg Barker reported as suggesting that Britain does not need more onshore wind farms, have also hit business confidence hard.

The government also recently announced that a planned Emissions Performance Standard (EPS) designed to address emissions from the power sector would not apply to new gas-fired stations until 2045. This would be a remarkable 'free pass' for the gas sector - especially given the fact that the UK's reliance on expensive imported gas is the main reason for soaring energy bills.

The fossil fuel sector has, in contrast, received numerous boosts. In the recent Budget, the Chancellor George Osborne granted up to 75% tax relief for decommissioning oil rigs in the North Sea and new allowances including a £3 billion new oil field allowance for "large and deep fields" to be opened up west of Shetland - despite the clear risks to the environment.

In short, the coalition government has effectively boosted subsidies for oil, gas and nuclear energy while the prime minister's backbench MPs complain vigorously about subsidies for renewables.

This week, the prime minister had a major opportunity to redress the impression that he has gone soft on the environment, to stop the perceived 're-toxification' of the Conservative party and counter the negative rhetoric coming from opponents in his own party.

Six years ago, on his return from the Arctic, he seemed engaged, determined and clear about the need to tackle environmental problems. What has happened to that engagement, determination and clarity of vision? We are left asking, above all, "where is the prime minister on the environment?"