Data for London: joining-up city data to build a better London for everyone

Chief Digital Officer for London
7 min readMar 29, 2023


This is a the first in a series of posts outlining London’s work on data. Below I run through the Data for London programme, what it involves, where it takes us and how to be part of it.

Data is now vital city infrastructure underpinning public service delivery, growth and innovation. Meeting city priorities like new jobs, community safety, affordable housing, good health and net zero will all rely heavily on data in its many forms. Its therefore important that cities create strong foundations for joining up, sharing and using data responsibly and effectively.

What is Data for London?

Data for London (DfL) is a programme to meet the Mayor’s 2021 Manifesto commitment to harness data and emerging technologies for our city by rebuilding the London Datastore to be a central register of London’s core data assets

It has two elements: first to rethink the London Datastore, the data platform which has served Londoners since 2010. The second is to set out the wider ambition for London as a leading city in the responsible use of data to create useful products, services and new value. This starts with a new framework so data can be effectively and responsibly linked and shared. Both of these are overseen by the Chief Digital Officer for London at City Hall.

Our mission is to join-up city data to build a better London for everyone. Over the next 5 years, Londoners and those that serve them will be able to access, share and combine the data required to address key challenges, supporting a fairer, greener, and equitable city for all. ​

To support this in November 2022 the Mayor launched the Data for London Board to advise on City Hall’s work. The Mayor also supports the London Office of Technology and Innovation (LOTI) which was established in 2019 to work closely with London’s boroughs on data, design and innovation. LOTI is already improving data collaboration through data projects, methods and information governance.

The Mayor’s Data for London Board

Why is joining up data important for the city?

Around 90 data services are operated by City Hall and data from the platform feeds into a significant number of projects, analyses and services externally. Data services feed the maps, apps and websites Londoners use every day. Data bolsters local expertise to inform, communicate and design policy with the public. Good data reporting drives efficient management of ​ service delivery and transparency. Predictive analytics help anticipate future trends and inform policy decisions, and sensor data enables real-time monitoring and alerts, as well as new services. Data is also a foundation for partnerships with London’s world-class research community so we can explore complex problems more deeply.

Does this involve centralising all data in London in one place?

No. The new Data London platform replaces and upgrades the existing London Datastore. It acts as a central registry of important data in London, not a central ‘data lake’ or all-you-can-eat smart city platform. With a registry, users can more easily link to datasets to develop insights, products and services for the benefit of Londoners. Like a big library book index, it helps users find the datasets they are looking for (although the rules of accessing may differ depending on the type of data requested and the body responsible for them).

Much of this data is already open but there is great potential in data services built on shared or closed data (see this Open Data Institute walkthrough for a good explanation of the difference between these categories of data) for specific purposes. Data of this nature is also protected by UK law which sets a series of legal and ethical tests around its use.

​This federated model therefore goes with the grain of London’s governance and is similar in approach to the one the NHS is currently developing for UK health data.​ The model requires data leadership from city government to set standards around areas like data quality, ethics and public participation so data can be joined up effectively and responsibly. This is why the platform will be augmented with a City Data Collaboration Roadmap.​

Participation by public bodies and other data holders is voluntary, not mandated, but public policy decisions in every major area will increasingly rely on data projects.

How will City Hall benefit from better data to serve Londoners?

Better data in one way or another lies behind most if not all of the Mayor’s work. As London’s strategic authority it almost goes without saying that having a city-wide view is critical. Many challenges defy administrative boundaries and 43% London households — 3.8m Londoners- live within 500 meters of a borough border.

Data will help the Greater London Authority serve Londoners better by powering the information in front-end digital products that allow Londoners to make important decisions, like the Mayor’s commitment to a Homes for Londoners search tool. Data and analysis on air quality, green infrastructure and planning is used to develop strong policies, such as decisions on where to prioritise clean air projects.

City Hall’s green infrastructure map

Programme reporting can be augmented over a complex range of partners to provide timely oversight, for instance, for the 100+ Good Growth Fund projects now being delivered by partners.​ Joined up data can create a ‘single source of the truth’ between agencies, as with the Violence Reduction Unit’s distribution of guidance and data to crime analysts in all 33 boroughs for their strategic assessments.​ Innovators can be brought in to pitch on problems, like in the ChallengeLDN’s open call to data science community to submit ideas on predictive analytics for infrastructure planning​.

The existing London Datastore currently has an extensive catalogue of datasets and high user engagement. However, the current platform needs to be improved so data users from wider local government, public services, civil society, research institutions, business and citizens themselves can better to:

share data more simply and securely​

find data on a single, searchable platform​

use data that is joined-up and presented with context

What does the roadmap involve?

The DfL roadmap adopted in March 2023 by the GLA following input from the Board, consists of 9 areas of work which will put in place the technology, methods and capabilities necessary to use and create better value with data.

The big takeaway here is that only part of this work is to do with technology in the form of a data platform: much of the work involves new methods and engagement with a wide variety of stakeholders, including the public and their elected representatives.

What’s the Mayor’s approach?

London’s new platform builds on our previous work and the experience of delivering data services to the city’s data users and collaborating with partners. It takes the central concept of the Datastore and improves functions, governance and ways of working — more often than not codifying existing practice and consolidating the work of key partners such as LOTI (on data ethics and information governance) and TfL (open data).

We’ve incorporated the Data for London Board steer that City Hall evidences additional value through several key data services acting as ‘demonstrators’ where both the public benefit of the service and a data friction to overcome are set out. For example the GLA’s live work with LOTI on rough sleeping data involves joining up datasets on vulnerable users, so the journey from discovery to completion will yield additional insights into how information governance issues are negotiated as well as the project’s policy goals.

What does the future state look like?

Where does successfully rebooting the new platform and completing the roadmap — fixing-the-plumbing, supporting data users and promoting good data citizenship- take us as a city?

The very recent explosion of consumerised AI is the tip of the iceberg of possibilities. Data is more than AI and the technology that harnesses it. Data is disrupting every sector, helping us tackle our greatest human challenges and is creating entirely new opportunities. Led by the Data for London Board we’ll be investigating the potential creativity data could unleash for our city.

We’ve seen, for example, how personal finance in the UK was/is transformed with Open Banking and travelling around London improved through TfL’s Unified API. On a city level, this imagines a future where city data can be transformative and one where new business or public service models can be developed to tackle some of our most pressing challenges, create new economic and social opportunities and harness London’s leading role in the emergent data economy.

This doesn’t mean increased tracking or monitoring of individuals, but does mean having a better understanding of how a complex and diverse city works and interacts with itself.

How can I be part of it?

In the coming months we’ll be posting more on how we’re proceeding with the new platform build; our plans for public engagement with the first ever London Data Week and progress on other areas of our roadmap. Connect with us on Twitter @LDN_data ; keep informed by visiting our data platform and sign up to the monthly newsletter; see the work of the Data for London Board.



Chief Digital Officer for London

@LDN_CDO & Data for London Board @MayorofLondon using data to support a fairer, safer and greener city for everyone​