When I first arrived in London a few years ago, one truth hit me immediately: the decision to buy or rent a home — one of the most important financial choices anyone makes in this city — is also one of the most opaque.
For expatriates like me, the challenge is even sharper. We arrive full of hope, yet we have no intuitive sense of what a fair price looks like in a place so different from home. As a data scientist, I felt a deep personal calling to solve this real, everyday problem. In early 2021, working alone on my five-year-old MacBook in a small room at the Seraphine Hammersmith Hotel, I began writing the first Python scripts to analyse London's property market. Those early scripts were created for a small Hong Konger community news webpage. From them I produced simple, shareable PDF reports packed with clear insights.
To my surprise and gratitude, the website analytics later showed that roughly one in every six Hong Kongers living in England had read those reports over the following years. That small statistic became my fuel. What started as a late-night side project for fellow newcomers had quietly begun touching real lives.
Over time, that humble script grew into something far bigger. Today it has evolved into OpenProp: a conversational AI analyst that turns the official HM Land Registry's 1.76 million raw transactions (2010–present) into instant, chart-backed answers that anyone can understand in plain English.
This project was never just about building another AI tool. It is the result of several deeply held convictions — economic, personal, patriotic, and a quiet but firm belief in justice through transparency.
I am a firm believer in the Chicago School of economics, particularly the ideas of Milton Friedman and Ronald Coase. At its core, their thinking revolves around transaction costs — the hidden frictions of time, money, and uncertainty that prevent markets from working as efficiently as they could.
In London's property market, those transaction costs are painfully visible: hours wasted hunting scattered data, expensive third-party reports that may be biased or outdated, and decisions made in the dark because official Crown copyright data — while publicly available — has always been difficult for ordinary people to analyse quickly and reliably.
OpenProp was created to cut through exactly those frictions — lower information costs lead to better decisions, fairer markets, and a more efficient and equitable society.
On a more personal level, I have always carried President John F. Kennedy's words in my heart: "Ask not what your country can do for you — ask what you can do for your country." As a Hong Konger who chose to build a life in the United Kingdom, I wanted to contribute, not simply receive.
We Hong Kongers bring drive, resilience, and a deep appreciation for opportunity. Building OpenProp is one way I try to repay the welcome this country has given me.
Buying or renting in London remains one of the biggest financial decisions most people will ever make. Yet for too long, clear, accurate, up-to-date, and truly unbiased market data has been surprisingly hard to access.
So I set out to democratise the official Crown copyright data once and for all. Every answer on OpenProp is generated from the same verified dataset that powers our fully open Kaggle notebooks. You can ask in plain English and receive not just words, but reproducible numbers and clear charts. There are no black boxes. The methodology is transparent. The calculations are verifiable.
The project was always designed with free access in mind. However, maintaining the data pipeline and delivering fast, reliable AI responses requires real time, skill, and resources. Every session pack purchased helps fund continued development and keeps the core experience open and accessible.
If any part of this mission resonates with you, I warmly invite you to try OpenProp today. Ask it anything. Verify the numbers in our open notebooks. And if you spot something we can improve, please tell me.
— Lorentz Yeung Founder, OpenProp