The environmental agenda was a key part of Cameron’s attempt to revive the Tory brand several years ago when he became party leader. Highlighting the impact of climate change on the Arctic went hand in hand with his broader call to let more “sunshine” into the Conservatives.

Blue + green = nice: that was the equation. But are cracks appearing in the stance?

Some in the environmental movement are concerned that the promises may not translate into a truly green reality. Andy Atkins, executive director at Friends of the Earth, said yesterday: “We should be getting far more detailed, coherent and ambitious (environmental) policy so close to a general election.”

One source has told me that Boris Johnson has slashed the number of people working in the GLA’s climate team - although I need to confirm his claim that the total personnel has fallen from 49 to 10 (update here later I hope).

UPDATE - it’s actually fallen from 49 to 25. The GLA have sent me an email telling me how many trees Boris is going to plant in London (10,000). It says: “We are confident that we can deliver more services (from City Hall and across the GLA group) for less to improve London’s environment.”

Meanwhile another green said there was a wider frustration that many of the delivery mechanisms crucial for fighting climate change were not in favour with the Tories. For example:

1] They are determined to slash regulation, especially from Brussels. Ken Clarke’s new promise to set up an anti-red tape “star chamber” - which will remove one new rule for every new one created - is a concern among the greens.

2] Regional targets. The Tories have promised to remove Labour’s attempt to push climate change targets down from Whitehall through the regions via a target system. Weak though it was, it was seen as a step in the right direction. It just doesn’t fit into the wider Conservative agenda of localism.

3] Money. When public finances are tight and Whitehall is about to be slashed, will the environment be among the priorities for the surviving civil servants?

4] Green taxes. Favoured by environmentalists - but feared by politicians. Will Osborne risk enraging Middle England further by tilting his inevitable tax increases away from the petroleum-based economy? It looks doubtful.

So how do they reach any green targets without the machinery to push them through?

The greens are grateful that Cameron shifted his party in their direction for a few years, helping to push through favourable legislation such as the feed-in tariff for energy. I suspect (people haven’t told me this explicitly) they now fear that he will abandon them once in power.

Will tomorrow’s speech by Cam have a major green element - or anything beyond broad brush strokes? Let’s wait and see.