All green eyes were on UK Prime Minister David Cameron yesterday as he made the first environmental speech of his tenure at the Clean Energy Ministerial summit. Would he be bold and visionary, committing the UK to a clean energy future?

Cameron famously used a ‘husky hugging’ trip to the arctic in 2006 to ‘decontaminate’ his Conservative party which had been drifting to the right since the late 90s, ceding the centre ground to Tony Blair’s New Labour Government. After becoming Prime Minister of a coalition Government in 2010, Cameron boldly declared that his would be ‘the greenest Government ever’.

Since then, Cameron gone quiet on the environment. It has been left to Lib Dem Ministers Chris Huhne and Ed Davey and Conservatives Greg Barker and Zac Goldsmith to fly the green flag, joined more recently by very robust pro-green growth decalarations from Deputy Prime Minister Nick Clegg and Foreign Secretary William Hague. So yesterday’s speech was a great opportunity to reset the compass on the green economy, rise to the level of commitment shown by many of his ministers and show some leadership. This is vitally important as everyone from civil servants to potential cleantech investors will be looking to the PM to see how the future is likely to unfold and will act accordingly.

Did he do it? Well, um, sort of. He said all the right things but, on my reading of the speech, failed to set the world on fire. Certainly his speech paled compared to William Hague’s recent comments in the Huffington Post on the crushing effect of fossil fuel prices on economic recovery and the opportunities for ‘green growth.’

As I argue in my book, The Green Executive, Leadership is the difference between the best and the rest when it comes to making sustainability happen. “If you don’t have your Chief Executive on board, you’ll get nowhere” as one of my clients remarked this week. This is as true for a country as it is for an organisation.

You can break Leadership into three interrelated parts: setting a vision, delivering on that vision and bringing people with you. With “the greenest Government ever”, Cameron set a superficially compelling vision, but one which was vague and, arguably, not that ambitious given the slow progress under previous administrations. On delivery the coalition has achieved quite a bit, but is far too quick to retreat in the face of dissenting voices in the press and from the backbenches, and got itself ensnared in the Feed In Tariff mess. But it is probably the third of these factors which is weakest – no-one knows where the Prime Minister really stands.

From a business point of view, it’s an interesting case study in the perils of lukewarm leadership. The breakthrough companies on sustainability (Interface, Marks & Spencer, Unilever, Procter & Gamble, Patagonia etc) have nailed their colours to the mast, made big bold changes and prospered as a result. Those who prevaricate get stuck in the boggy no-man’s land of incremental improvements, mediocre business returns and disillusioned stakeholders.

Going back to politics, in the same way the most sustainable companies have benefited from going green, there’s a big opportunity for Cameron here. He has struggled to define his Government beyond deficit reduction and the hazy ‘Big Society’ concept which has never coalesced into a tangible policy agenda (a worrying precedent). Cameron could make going green exciting, visionary and a path out of our economic predicament. He could face down his backbenchers (it never did Tony Blair any harm) and plant his flag clearly in the centre ground.

Show some leadership in other words.

Full disclosure: While this blog is avowedly non-partisan in its politics and I am writing in my role as MD of Terra Infirma Ltd, I am also a member of the Liberal Democrat party and a city councillor.