JOHN TAVENDALE, 55, Project Manager

I’m from Montrose, 35 miles up the road. I live in Dundee and the Kengo Kuma design was the one I voted for. It was extremely beautiful. I also looked at it and thought: ‘I don’t know how you build that.’

Basically, a project manager is the client’s representative. To manage the delivery of a project usually from the briefing that goes to designers, the selection of the designers, the development of the design through to the procurement of construction, delivering the construction project and the cost management of all that.

On a project like this it’s a little more complex because there are many stakeholders who need to know it is being delivered efficiently and effectively.

It was incredibly challenging structurally to make that building work. It’s two inverted pyramids and in the middle of each is a concrete core. In this structure everything is twisting. It’s not like a simple vertical building.

I always said the two real serious challenges were building it out in the river estuary and the structure itself. That’s where the money is.

The problem with building it in the river is an obvious one. There’s no site. It’s a river. It moves.

How do you create that site? Is it rock filled in? is it pilings? To do that you have to build a cofferdam into the river, 100 metres out. That was going to cost vastly more money than anybody could know at the outset.

The river is a protected habitat. A site of special scientific interest. To satisfy Scottish Natural Heritage we had to do a long-term study of all the species in the estuary. We found that we had harbour seals which are an endangered species on the east coast and we had sea lampreys, which I had never heard of, and they are also endangered.

With escalating construction time and cost risk I took it back to the stakeholders and recommended we consider moving the building onshore.

Kuma, I have to say, has been incredibly respectful of the stakeholders. All through the design process he has always taken on board the concerns and issues and very creatively found positive responses, often better than the original. That’s a remarkable talent. I haven’t seen that very often.

There were plenty of sleepless nights. The darkest time literarily and metaphorically was probably November-December 2015, January-February 2016. The challenges in building such a unique structure were proving more difficult than initially planned for. The winds were blowing, the cranes were unable to work. To have guys out there in the dark and the wind and the rain putting form up with just a two-millimetre tolerance is asking an enormous amount. But they did it.

When we got past what we call ‘the knuckle’, the second level where these leaning-out wacky walls become almost straight we knew we were away.

It’s not a building that I’ve grown tired of at all despite seeing it every single day. I still look at it and think: ‘Well done everyone. What a fantastic achievement.’