Jonathon Porritt, one of Britain’s leading environmentalists, has attacked the Treasury for being “startlingly arrogant” and for dragging its feet over sustainability.

This month Porritt steps down as chairman of the Sustainable Development Commission, an independent government watchdog, after occupying the role since it was founded nine years ago.

He said: “Looking back now, as I am in my last few days, I see a terrain of wasted opportunity. I am not saying the only reason is the intransigence of the Treasury, but I do think the Treasury has killed a lot of the energy around sustainable development.”

Porritt, who is being replaced by William Day, gave the Treasury credit for hiking the landfill tax and for commissioning Sir Nicholas Stern’s review on the economics of climate change. However, he added: “Too often they have been foot-dragging and obstructive.”

He said: “It is a startlingly arrogant part of government. There is almost no curiosity about sustainable wealth creation. There is no readiness to interrogate the macro-economic model. SDC produced a report, Prosperity without Growth, in an attempt to start a debate on redefining prosperity, but we were met with a weird mixture of hostility and indifference.”

According to Porritt, the Treasury was slow to set an example on sustainability through programmes such as the private finance initiative (PFI) or Building Schools for the Future (BSF). He said he tried to engage with the Treasury over PFI, which he saw as one of the main mechanisms by which the government could send out signals to the private sector about promoting sustainability. But, he said: “The whole PFI process from 1999 onwards has been a sustainability-free zone.

“With the Building Schools for the Future programme it took four or five years for the Treasury to understand it had to have sustainability at its heart. It was straight Treasury obstinacy.”

Since it was founded in 2000, the SDC lobbied the government consistently to use its multibillion-pound budget to promote sustainable development through its procurement of buildings, goods and services. But Porritt said his efforts fell on stony ground for years. “At meetings relatively senior civil servants from the Treasury were sitting there glowering and wondering what they could do to scupper things when they got back to base,” he said.

“Last year, the Treasury realised government had to play a role but it was blindingly obvious all along.”