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Lucy Siegle: Hello and welcome to WSP’s Positive Impact Podcast. I’m your host, Lucy Siegle.

In this series, we explore the ideas, innovations and voices shaping a more sustainable, resilient and future ready world.

Today, we’re talking about ageing infrastructure. From roads and railways to water networks and public buildings, much of the UK’s infrastructure is nearing – and in some cases has passed – the end of its original design life. At the same time, budgets are tight and demands continue to grow.

So how do we maintain safety, plan for renewals, and make sure we are future proofing what we already have?

I’m joined by two brilliant guests with deep insight into this challenge: Steve Denton from WSP, and Professor Andrew McNaughton from Network Rail. Welcome to you both.

Lucy: Steve, why is ageing infrastructure such a pressing issue right now?

Steve Denton: As engineers, we often talk about roads, bridges and assets – but what really matters is the function those assets serve.

When we get up in the morning, we expect the lights to switch on, water to flow from the tap, and transport networks to get us where we need to go. These assets are the hard wiring of our country. They underpin how society functions and are critical to the economy.

The challenge we face today is driven by three main factors.

First, the age profile of our infrastructure. Like cars or houses, assets require more attention as they get older.

Second, climate change is placing increasing pressure on those assets.

And third, societal expectations continue to rise.

Taken together – and set against limited and competing resources – that creates a significant challenge.

Lucy: Andrew, what’s your perspective?

Andrew McNaughton: We talk a lot about 2050 or 25 years from now, but the reality is that almost every asset we use today will still need to function then.

We are reliant on what we already have – and with older infrastructure, we rarely know as much as we would like. When engineers design something new, we talk about factors of safety. With ageing infrastructure, we are often dealing with a factor of uncertainty.

We don’t always know exactly how something was built or maintained, yet we still need to make judgements about how it performs tomorrow, next year and decades into the future.

Lucy: So what does good asset management look like in practice?

Andrew: Sometimes, it starts with knowing how much you don’t know.

One of the biggest prizes in asset management is deciding when you don’t need to do something. That is often the most cost effective engineering decision – but only if it is made deliberately and based on good judgement.

Steve: At its core, asset management is about decision making.

You tend to come back to three questions:

• What is the right intervention?
• When is the right time to act?
• How do we make a compelling case for the resources to do it?

The key is framing those questions around purpose – what is this asset here to do? That then drives better use of data, better understanding of uncertainty, and better long term decisions.

Lucy: Are there good examples we can learn from?

Steve: There is actually a lot of good practice already in the UK. Despite the pressures, most of the time infrastructure performs remarkably well.

Internationally, higher reliability is often down to differences in asset age or operating context rather than fundamentally different approaches.

Andrew: Switzerland is often highlighted. One lesson I’ve learned there is this: leave something as long as reasonably possible – but when you intervene, do it properly.

That does not mean gold plating. It means making decisions that will last and not need repeated fixes.

Lucy: Can you give us an example of asset management done well?

Andrew: A standout example is the reconstruction of a railway embankment on the East Coast Main Line near Darlington. It was built around 180 years ago using the materials and techniques of the time and had been slipping for most of its life.

In just two years, Network Rail and its partners rebuilt the embankment so it can now carry more traffic at higher speeds – without closing the line or imposing speed restrictions.

They focused relentlessly on the purpose of the railway – serving passengers – and used innovative techniques to achieve that. For me, that is excellent asset management.

Lucy: How do you balance cost, carbon and risk when managing assets?

Steve: I would challenge the idea that these factors are in conflict. In most cases, they are aligned.

Doing the right maintenance or renewal at the right time is the right thing for cost, carbon and risk.

One of the biggest contributions engineers can make to decarbonisation is extending the life of existing infrastructure. There is nothing more wasteful than replacing something that could continue to perform with good judgement and expertise.

Andrew: And when we talk about risk, we are not just talking about safety. There is also performance risk, financial risk, user risk and business risk. If decisions are made at the right time, these considerations tend to move together.

Lucy: How can innovation help make smarter decisions?

Steve: Digital tools allow us to rethink how we understand assets. In the past, engineers often spent their whole careers looking after the same infrastructure, developing deep insight into how it behaved.

We can recreate some of that through better data, imaging, and digital analysis, allowing us to track how assets change over time and predict future behaviour.

This moves us from static snapshots to informed, long term decision making.

Lucy: What mindset shifts are needed?

Steve: We need to stop taking infrastructure for granted. When we turn on the tap or stand on a train platform, we expect everything to work – but that reliability is the result of deliberate planning and intervention.

Planned disruption today is far better than unplanned failure tomorrow.

Andrew: We also need more curiosity. Innovation often comes from small, emerging organisations. Not every idea will be right, but progress depends on being willing to explore new approaches in a managed way.

Lucy: If you could change one thing, what would it be?

Steve: I would stop society taking ageing infrastructure for granted. Valuing it properly means valuing the people who maintain it, improving safety, and ensuring we attract the skills needed for the future.

Andrew: I agree. We need to raise the profile of asset management beyond engineering and into policy making and public discourse. These roles are demanding, vital and hugely rewarding.

Lucy: That’s all we have time for today. Thank you both for such a thoughtful and wide ranging discussion.

And thank you for listening to Positive Impact. If you enjoyed this episode, remember to subscribe, rate and share. You’ll find more information and resources in the episode description.

Join us next time as we continue exploring ideas shaping a smarter, greener future.