'We didn't need to dig the foundations on this one, ' says Chris McCarthy, of multidisciplinary engineering practice Battle McCarthy, leaning back in his chair and looking rather pleased with himself. 'We just used a mine clearance vehicle to do that.' How can engineering be suffering such a serious recruitment crisis when McCarthy and his partner, Guy Battle, are potential figureheads? With their stories of building universities on Angolan minefields, one would have thought that these two would be a marketing man's dream.
How many 16 year olds would be able to resist the lure of a job that sees you flying around the globe putting up incredibly complex structures in some of the world's most interesting places? And how many adults would be able to resist the opportunity to spend vast swathes of time in the Big Apple working with one of the world's most famous architects on 'greening' the highest profile construction project in the universe? Daniel Libeskind's Freedom Tower is that important.
Holborn-based Battle McCarthy is not the biggest engineering firm in the world but must surely be one of the most unusual. McCarthy - a fop of shambolic hair and public-school physics teacher mannerisms - is a structural engineer and Battle, the younger and clearly trendier of the two, is qualified in the environmental disciplines. It is hard to resist mental references to the 'original odd couple' when you meet them and see their relationship.
What makes the firm more unusual still is its commitment to landscape architecture.
This is an abnormal set-up and must have taken a major leap of faith for the firm's founders when they decided that people really needed a company to design systems that integrate the air conditioning with the external shrubbery and car parking. However, it all make sense when you realise the stock that Battle, in particular, puts in reed beds as part of drainage and plumbing systems.
But without doubt the most interesting aspect of the firm is the work it is doing with Libeskind and SOM's David Childs on the World Trade Center site in New York.
Battle was brought in back at the scheme's inception, two years ago, to help out on the designs, after gaining a North American reputation developing the new stadium proposals for the New York Jets in Manhattan.
What nobody could have expected was that Battle McCarthy would come up with plans for the largest urban windfarm in the world on top of the 1,776-foot Freedom Tower. In a country that has spent the past three and a half years backing out of its Kyoto Protocol targets for the reduction of CO 2 emissions, this must seem an amazing proposal.
Even on this side of the pond, it seems pretty unusual. The concept design shows something resembling a transparent second tower balancing on top of the office skyscraper, with a mixture of turbines each facing into the prevailing wind. The project will, when it eventually enters the public consciousness, almost certainly leave Battle McCarthy as the trendiest engineer in the world. You can imagine this role sitting easily on Battle's shoulders but perhaps not with McCarthy.
Throughout the interview, both Battle and McCarthy behave more like a married couple than business partners: both talking at the same time, contradicting one another and teetering on the edge of bickering.
But what of working on the World Trade Center designs? The first and rather striking observation is that between the pair of them they only manage to make one reference to Libeskind, while simultaneously talking in the most glowing terms about SOM and Childs.
What does this mean? Can this possibly reflect the pair of them taking sides in what is the world's most well-known architectural dispute? Suddenly, when this subject comes up, the atmosphere changes. Gone is the almost child-like babble of chat and enthusiasm, replaced with an on-message political response. There's no chance that these two are going to be entrapped by leading questions.
'We worked on both the proposals drawn up by SOM and those by Libeskind, ' says Battle, looking a little uncomfortable. 'I feel that the scheme will benefit from the way that the two were drawn up separately - the Freedom Tower is definitely better for it.' When pushed about the ongoing row, both wriggle uncomfortably. 'This was and is a great scheme, ' Battle insists. 'We speak to both architects regularly - for example, Danny [Libeskind] was on the phone this morning.
'But what is really important is that we are developing an amazing project, ' he adds. 'Just imagine the fact that this wind farm is going to produce 40 per cent of the required energy for the entire office. That is incredible.' The interview rambles on for the best part of an hour, with topics cropping up and vanishing without any discernible pattern.
Both men take it in turns to hold court on various issues that they hold dear - ranging from the government's failure to support knowledge-based firms working overseas to the potential use of the energy found in the tension of a skyscraper tower.
What becomes completely apparent is that the pair of them have a very clear concern for - and are probably mildly obsessed about - the world's ecology and environment. But then you probably have to be, to spend large chunks of your time worrying about the 'crapping pattern of office inhabitants and the way that it effects drainage patterns'.