'That rhythm of high peaks and modest peaks interspersed with slumps' - the classic boom-and-bust cycle - 'is a function of the old language,' says David Cadman. 'That is the type of property market that language gives you. If you were in a state of sustainability you might see a rather different type of market . . . I suspect it would have less volatility.' Cadman, whose cv includes a partnership at Savills, professorships at Reading and ucl, a fellowship at Cambridge, and co-foundation of the consultancy Property Market Analysis, as well as his current venture, Environmental Governance, makes a persuasive argument that 'the language that we use to to describe our relationship [to buildings] becomes concrete. If you are not satisfied, don't use the old language. It will bring you back to where you started. It has a rigid inevitability'.
Having been scarred by a short period as a developer either side of the 1970s boom, he has spent the last 20 years trying to understand the relationship of the property market to the economy in general. That first found expression in his book, now in its fourth edition but originally published in 1977, called The Property Market, which itself became a primer for his students as he took up a fellowship in development at Reading in the late 1970s. 'If you have a questing nature you would ask, 'why did it happen?' and conclude that it would be better if it didn't recur.'
That's when Cadman began to find that language can be an encumbrance. He started looking for an alternative voice among indigenous peoples, which began to focus on Celtic mythology and especially its appreciation of the annual cycle. Over time that brought him to the debate about sustainability. Meanwhile, when asked to formulate a development strategy for the property company, 'I realised that I needed to know something about the economy'. That inspired him and a colleague to found the successful Property Market Analysis, from which he retired in 1996.
Then aged 54, he did not remain idle. The first Business in the Environment Survey (covering the 'environmental engagement' of ftse 100 companies) showed that Land Securities did not score well. He approached the company with an offer to help. It was an opportunity to combine his interests in sustainability with his knowledge of the property industry. At the beginning of 1997, while also a professor at ucl's school of public policy, he launched Environmental Governance.
This has now grown to conduct the Property Industry Survey, a private report but using the bes criteria. The second survey, now in preparation, 'shows improvement. It shows that the property industry is taking this issue seriously, and that the industry is addressing it in a workmanlike manner . . . and improving', he says confidently. He also works with contractors, and sits on Tarmac's environmental advisory panel. The same issues constantly recur: energy, water, waste management and transport: in the property industry 'there are all sorts of questions about capital cost and cost- in-use, and the extent to which there could be a growing partnership between landlords and tenants'.
Cadman sees reason to be optimistic in the growing awareness of the need for 'connectivity', as defined by New Labour egghead Geoff Mulgan, which he sees as being close to his own concept of 'relatedness' and the underlying shift towards 'joined-up thinking'. It is the linkages which are important, he says. Many of these themes come from his study of Celtic mythology. A few years ago he wrote a charming fable entitled The King who Lost his Memory - a semi-autobiographical tale about a king's dreamlike journey to rediscover the key to regenerating his land. With shades of the Grail legends, it has resonances for today.
He has turned to literature to evolve this understanding, but architects might do it in built form, in the real environment. He respects Rab Bennetts' conclusion that a green building should not imply higher construction costs, but might need more investment in design. He also admires 'the beauty of the vaults' in Bennetts' work, and likens them to early Christian church domes. 'Perhaps we need to be more elemental,' he suggests about design.
He does believe that the 'new language' which is vital to reconfigure the property industry into a sustainable activity will have to be 'poetic', and adds, 'Insofar as architects are imbued with some dimension of the poetic, they have a very important role.' He doesn't envy their position, standing between visions and technical solutions - 'it must be a very hard place to stand' - but you need 'such a grasp of the technical so that you can be poetic'. If architects keep working in the 'old technical/financial mode', they will 'keep producing the wrong thing; they need to engage with something large'.
Otherwise, he claims, 'I am not sufficiently slotted into the architectural world'. But that could also be up to architects, for his vision reaches beyond both the mystical and emotional poles of architecture, and well into the mechanics of the property industry, some way beyond its practical and prosaic pole. If Cadman can't fill the gap in concrete form, perhaps architects should.