Like collaborative working, being sustainable was a child of the boom years.

But just because output is predicted to fall 12% between 2008 and 2010, construction companies can’t forget the green agenda. As Paul King says, tackling it is still one of the biggest challenges we face. Hence our Detox issue.

The legislative machine is still rolling; for example, there will be a consultation on next year’s reform of Part L, another step in the march to zero-carbon buildings by 2019. The carbon reduction targets are incredibly ambitious and there is a long, long way to go. A nice story published this week illustrates our hidden energy use: a Harvard research scientist reckons two Google searches produces as much carbon dioxide as boiling a kettle (add up those across your company, if you dare).

The government is still finding its way. For example, level six of the Code for Sustainable Homes could be redundant, as recent consultations open up the possibility that renewable energy can be generated off site, which is what the companies have being calling for. And the industry is still unsure how do zero carbon and make money. Some solutions don’t always work, for instance sheep’s wool insulation and low-flow taps. On top of that, our survey with the Energy Saving Trust shows that clients are unconvinced about the merits of green design. On the credit side, there are some areas where the government is leading by example, for example Defra’s new office in Northumbria.

Three years after our 99% campaign highlighted how essential it is to green our existing buildings, it remains a gigantic problem – although our economics piece shows there are some quick, cheap wins to be had. Then there’s Gordon Brown’s heat and energy saving strategy, due out for consultation in the next few weeks. Let’s hope that sets out a plan for reducing emissions from existing stock.

And amid these practical, technical and policy challenges are the difficult choices of balancing economical and environmental imperatives

And amid these practical, technical and policy challenges are the difficult choices of balancing economical and environmental imperatives, as highlighted by the rumpus over Heathrow’s third runway, which has split the Cabinet. Airport expansion has already led to the re-emergence of modern-day Swampies armed with new tactics. Our interview with John Sauven, the executive director of Greenpeace, gives an insight into those. His organisation has already caused disruption to a new coal-fired power station in Kent. What will happen when we start building nuclear reactors? And how does the industry deal with it?

One thing’s for sure: we need some new industries to help us out of the recession. In the eighties it was financial services. There’s a view among some politicians and economists that green starts-up will be the answer for the noughties. And if it is, construction can play a major part in making it happen.

Happy birthday to you

Winter is freezing, the boom has busted, land prices are 30% down, nobody can sell a house and a Scottish engineer called George Balfour has just joined with Andrew Beatty, an English accountant, to found a contractor. That was 1909 – and isn’t it surprising how little changes in 100 years? As the firm celebrates its centenary with a supplement in Building, the enterprise and vision that helped it flourish is still very much in evidence. Balfour Beatty is defying the latest downturn with £12bn turnover and it looks likely to join the FTSE 100 soon. It has blotted its copy book at times, notably with the Hatfield rail disaster, but its recent record suggests it has learned from those mistakes, and the position it’s in is the envy of many a chief executive. Happy birthday, Balfour Beatty. Here’s to the next 100 years.