Ask the Expert – January 2025

In our Ask the Expert section, Ian Quayle, Managing Editor of Property Law UK, interviews seasoned legal professionals, and legal industry suppliers. He poses a series of questions regarding the current landscape of residential conveyancing or commercial property transactions, encouraging them to impart their knowledge and expertise to the readers of Property Law UK magazine.

In this month’s edition, Ian is joined by Henry Crosby PhD, the Founder and CEO of Martello.

Ian Quayle (IQ) Why did you choose the career of a geospatial data scientist? 

Henry Crosby (HC) My journey into geospatial data science began in 2013 with a PhD at the University of Warwick, focusing on automated valuation models – essentially predicting residential property prices. Back then, machine learning (or AI) in valuation, geospatial, and property was foundational. Computers were good at collating local information to recognise market fluctuations, but the models didn’t yet exist to fully take advantage of this. 

During this time, I came across Tobler’s First Law of Geography: “Everything is related to everything else, but near things are more related than distant things.” This concept sparked my imagination—the idea of building localised geospatial models that could work globally. 

After my PhD, I joined Nimbus Maps as their first technical employee, leading the geospatial database behind their software. Later, I became Associate Director of Data Science at Carterwood, where I helped develop niche software for care homes and older people’s housing developers. These roles gave me a deeply UK-focused understanding of geography, which I enjoy immensely. 

What I love most about geospatial data science is the community it brings together. I work with cartographers, satellite image experts, map creators, AI specialists, and software engineers – it’s a small but fast-growing world of curious, passionate people. 

My favourite part of the job is optimizing code and working with historic maps, from the Industrial Revolution to today. That era of history fascinates me—it’s like uncovering stories from the past. Historic maps reveal history, culture, and change in ways nothing else can. 

(IQ) When and why did you decide to create Martello? 

(HC) I started Martello in 2020 and went to market in 2024 to address a recurring problem with environmental searches. While they’re often the quickest to come back, they’re not always the quickest to resolve. Conveyancers frequently face follow-on actions—chasing warranty certificates, obtaining planning evidence, filing Freedom of Information requests, or arranging indemnity policies – creating extra work for conveyancers, buyers, and sellers. 

I believed we could provide a more “final” answer, giving clear, actionable advice for consumers upfront. Environmental searches are often the part of the search pack that conveyancers feel least comfortable with, so it made sense for environmental experts like us to take on that additional work. With our experience, we can resolve these queries more quickly and accurately. 

Ultimately, Martello is about reducing the workload for conveyancers, taking on the responsibility ourselves, and making the process more efficient. It’s a win-win: less time spent on searches and lower liability for conveyancers. 

My favourite thing about Martello is our team. We’re a passionate, clever, interdisciplinary group of conveyancer empathisers, including geospatial experts, software engineers, cartographers, data engineers, AI specialists, and experts in geotechnical analysis, contaminated land, flooding, and climate and commercial law. Together, we’ve built something truly unique to deliver exceptional solutions for conveyancers and their clients. 

(IQ) Can you explain to conveyancers why an environmental search and report is necessary in the case of a residential conveyancing transaction and a commercial property transaction? 

(HC) Of course, environmental searches are one of the most important parts of the process, simply because they deal with risks that can have a huge impact on people’s lives. For residential transactions, we’re talking about protecting what is often someone’s most significant investment – their home. Flood risks, contamination, or ground instability don’t just affect property value; they can also have serious implications for physical and mental health, safety, and financial security. 

When it comes to commercial properties, the stakes can be even higher. Businesses rely on their premises to operate, and unexpected risks like flooding or contamination could lead to disruptions or even legal challenges. 

Arguably, environmental impacts, such as flooding, have a far greater implication on finances, health, and safety than almost anything else covered in the searches, legal or otherwise. By having a thorough environmental report, conveyancers can provide clients with clear, actionable insights, helping them make informed decisions and avoid potential pitfalls. Also, why risk the liability that would come your way, by not doing the search? 

(IQ) I know you are at the forefront of climate change reports. Why do you think that a climate change report is necessary for a buyer client in a residential and commercial property purchase? 

(HC) Ultimately, climate change means hotter summers, wetter winters, and more frequent extreme weather, increasing physical risks to the UK housing stock. 

Many assume that Scandinavian countries handle colder climates, Spain deals with heat, and the UK, being mild, is not at risk. However, our properties and infrastructure were built for this mild climate. With global temperatures rising by 2–3°C above pre-industrial levels, the UK is becoming increasingly unprepared for these changing conditions. 

Another misconception is that predicting physical risks is unreliable because “weather forecasts are never accurate.” In reality, we’re not predicting weather but identifying the topography and geography most at risk from trending climate changes. For example, areas prone to flooding or overheating will likely see these risks increase. 

The goal is to stop people assuming their properties will always remain safe. Cost-effective mitigations, like raising floor levels, improving drainage, or planting shade trees, can be implemented now. Acting early avoids later consequences, like higher insurance costs, decreased property value, or disrupted family life. 

For residential buyers, factoring climate change into searches ensures long-term safety and financial security. For commercial buyers, it safeguards operations and prevents costly disruptions. 

By addressing climate change in searches, conveyancers help clients avoid surprises, future-proof investments, and protect well-being. Importantly, conveyancers also protect themselves, particularly with the upcoming Law Society practice note on climate risks. 

(IQ) Have got any case studies or examples of why an environmental search and report is necessary in a residential conveyancing transaction? 

(HC) We met a homeowner who shared her devastating experience of being affected by Storm Henk on January 2nd, 2024. When she purchased her property, there had been a historic flood back in 2007, but no environmental report was ordered during the transaction. When the storm hit, her property was overwhelmed by groundwater flooding, with water rising to 3 feet inside the home. 

She was forced to evacuate immediately with her three children and two dogs, first moving into an Airbnb for two weeks, then into rental accommodation chosen by her insurance company. Nearly a year later, she and her family are still unable to return home. Because the insurance claim was so extensive, two different assessors have been involved, and the repair process has been delayed. The homeowner is now waiting to move back in but the experience has left them unable to feel secure living there again and unsure whether they will be able to sell. 

What’s striking about this case is that flooding is a known risk in the Gloucestershire, where the property is located, but no environmental report was ordered at the time of purchase. Retrospectively, we ran our search on the property and clearly identified its susceptibility to groundwater flooding—an insight that could have influenced the decision to buy, or at the very least, allowed the her to put mitigations in place before disaster struck. 

She was fortunate to have insurance, which has covered much of the financial burden, but the emotional and physical toll on her family has been immense. 

The Law Society explicitly highlights the importance of ordering necessary searches during conveyancing, and their Flooding Practice Note clearly sets out the risks and responsibilities. Cases like this serve as a stark reminder of why environmental searches are not just a box-ticking exercise but a critical step in protecting homebuyers from life-altering events. 

(IQ) What are your future plans for Martello? 

(HC) Our development roadmap is packed, and we’re growing quickly to meet increasing demand while keeping up the pace of innovation. Right now, we’re focused on delivering mining solutions that truly raise the bar, going beyond the current standard to offer something that’s practical, reliable, and easy to use. 

One of our biggest priorities is improving the experience for both conveyancers and home buyers. Everything we’re working on is designed to make environmental searches simpler and more intuitive. We want to help home buyers better understand the information they’re given, reduce the time conveyancers spend on searches, avoid unnecessary shocks or extra actions, and lower liability wherever possible. 

(IQ) Finally, changing tack, what do you like to do in your spare time? 

(HC) Outside of work, I love spending time with my wife Claire and our two kids, Charlie and Milo—who keep life fun and chaotic! I’m also a fan of cold-water swimming with mates, which is a refreshing (if slightly mad) way to clear my head. 

I enjoy playing the piano to unwind, and I’ve always been fascinated by history—especially post Industrial Revolution—so I often find myself exploring historic maps or learning about how landscapes have evolved. And when there’s time, I’m working on setting up a family-friendly rock and roll band. 

Henry Crosby is the founder and CEO of Martello, a company providing independent environmental searches for conveyancing professionals. With a PhD and a passion for clear, data-driven insights, Henry is on a mission to help conveyancers navigate environmental risks with confidence. He brings a witty and supportive tone to industry discussions, championing innovation while understanding the pressures conveyancers face. Outside of work, he’s a parent governor focused on maths, a keen advocate for engaging technical problem-solving, and a musician who plays both piano and guitar.