I am, of course, talking about Charlie, who seems to have a knack for dividing opinion. Take his latest speech, for example: the 2009 Richard Dimbleby lecture, in which he reasserted his already well-known credentials as the royal poster-boy of environmentalism and everyone’s favourite posh greenie. Last year he came out top of a Country Life survey to find out who people saw as the ‘guardian of the countryside’ and Time magazine has called him ‘one of the world’s leading conservationsists’. Many people with an environmental agenda themselves evidently think that he is well-intentioned and also that his position outside of parliamentary politics and interest groups gives him a refreshingly non-partisan voice.

In his speech he stressed the need to ‘maintain balance between keeping the earth’s natural capital intact and sustaining humanity on its renewable income’.

‘We are not separate from nature’, he argued, ‘like everything else, we are nature.’

This is the kind of sentiment which wins Charlie praise from environmentalists. But his attitude to architecture in particular as represented in this speech is revealing, and relates to his recent clashes with one of the more prominent members of the architectural establishment.

He said, for example, that ‘I have talked long and hard about this for what seems rather a long time – but it is yet another case where a rediscovery of so-called “old-fashioned”, traditional virtues can lead to the development of sustainable urbanism.”

It’s the ‘old-fashioned’ part of this which  is most interesting. There’s no doubt that there is a lot to learn from the building methods and ways of life of the past. But I contend that Charles is interested in sustainability mainly in the sense of sustaining his own interpretation of what England is: a green and pleasant land of noble princes and toiling peasants, a land of village cricket greens and housing styles named after royals of the past few centuries: Tudor, Queen Anne, Georgian and Victorian. This sense of continuity, after all, supports his own standing as a member of the monarchy. And Charles was even keen to praise King Henry VIII as an environmentalist in his speech just to make plain to any of the less enlightened plebians that may have been listening that the royal family have a long and noble tradition of caring for nature.

The bizarre historical pastiche of styles at Charles’s pet project of Poundbury is what he would like to see in new housing developments across the country. Yet it is clear that modern, experimental technology and methods as well as far more ancient, vernacular building techniques can both play a significant role in creating better homes for people and the natural environment in the twenty-first century.

The Prince’s Foundation for the Built Environment has been working on an interesting Passivhaus-based design at the Building Research Establishment (BRE) recently which suggests that even Charlie can see that there is a requirement for innovation. Yet the overall aesthetic impetus behind his thinking on architecture - a kind of fudged, nostalgic, conservative classicism - is surely an impediment to change towards better housing rather than a catalyst.

And if you’re not part of the solution, as the saying goes, you’re part of the problem.