What’s buried beneath our feet? New National Underground Asset Register digital twin MVP goes live in London

Chief Digital Officer for London
7 min readApr 21, 2023

City Hall hosted a great example of city-wide data collaboration with government this week with the launch of the National Underground Asset Register MVP: a digital twin of buried assets to aid infrastructure project delivery and protect worker safety.

Below our feet lie thousands of kilometres of pipes, cables and ducts that, without much fanfare, enable us to live and work in London. This network of underground or ‘buried assets’ is owned by many different bodies including local authorities, major utilities and transport providers among others. This has created a complex web of networks and systems across the city resulting in friction and delay in many construction and infrastructure projects.

Collaboration between government, city hall, boroughs, industry and the data sector

Since 2019, the Greater London Authority’s (GLA) Infrastructure Team has been a delivery partner to the Geospatial Commission (Department for Science, Innovation and Technology) in the journey of developing a digital twin that will revolutionise the way we install, maintain, operate and repair our buried infrastructure called the ‘National Underground Asset Register’​ (NUAR)​.

NUAR is a digital map that will allow underground asset owners and their supply chain to query an area and instantly see data from infrastructure providers and local authorities on one map. The programme has now reached a major milestone in publishing its ​m​inimum ​v​iable ​p​roduct (MVP) which is being rolled out to asset owners and their supply chains in London, the North East of England and Wales.

NUAR Walkthrough

The need for NUAR

Over four million holes are dug in the UK each year, many in the wrong place due in part to the lack of awareness about who operates underground. Excavators in London face the additional challenge of a highly congested underground landscape as a result of London’s rich history.

In the City of London, excavators are still finding remnants of wooden pipes that were laid in the 1600s to carry water. Today, we continue to find ways of making our streets healthier by improving local drainage solutions th​r​ough Sustainable Urban Drainage Systems (SUDS).

Asset owners in London, and across the country, have limited real-time visibility of one another’s asset types and locations as information is maintained and managed by asset owners independently. Where sharing of data happens, the format and structure of data isn’t standardised, resulting in a lack of consistency between one asset owner’s presentation of their asset information to the next.

This inefficient method of information sharing can in extreme scenarios lead to injury to the excavator but more commonly cause delays of on-site work. By engaging with ​over ​650 asset owners across the country and standardising the presentation of asset information through a shared data model, NUAR will increase efficiency and safety to excavators when digging on site.

City Hall’s role in NUAR

The GLA has played an instrumental role in getting NUAR to the place it is today, with a pivotal initial trial being carried out in 2018 between TfL, GLA and Thames Water called HADES (Highways Asset Data Exchange System). The aim of this project was to attempt to display highways asset data in a central database.

The success of the HADES pilot and a similar trial in the North East of England led Cabinet Office to formally launch — with the endorsement of the Mayor’s London Infrastructure Group (LIG) — a pilot of the underground asset register in 2019. Since then, working with the Geospatial Commission and Atkins, the GLA has been integral in the delivery of the subsequent phases of NUAR — the preparation phase in 2020 and build phase since 2021.

The GLA’s key role in NUAR today is to manage the engagement with the 50+ asset owners who make up London’s underground landscape. This includes initial engagement, signing legal agreements, obtaining data and ensuring it is transformed successfully to the NUAR data model before it is loaded to NUAR itself. We also advise the Geospatial Commission on the development of the programme more broadly.

As a strategic body the GLA is well placed to coordinate the many stakeholders and bring them together for a common purpose. The GLA’s infrastructure team’s role is to lead and work between those who shape London’s infrastructure, developing solutions to cross-cutting issues and aligning work towards the Mayor’s priorities.

We take a data-led approach to infrastructure coordination and have long pioneered the use of data and innovation tools to inform strategic planning, drive collaborative working and delivery, and create evidence-based policy. For example, we delivered the ​​London Infrastructure Mapping Application to coordinate utility works to reduce ensuing road congestion in 2015 and have continuously improved and expanded the service since then.

London’s underground asset owner community

London’s underground asset owners can be categorised into three broad groups: utilities, local authorities and non-utility/non-local authority actors. 12 major utilities own the lion share of this network and regularly dig up our roads to install, repair or upgrade their assets. These are:

  • Electricity: National Grid, SSEN, UKPN
  • Gas: Cadent, SGN
  • Water: Affinity Water, Essex & Suffolk Water, Anglian Water, Thames Water, SES Water
  • Telco: Openreach, Virgin Media

Smaller utilities operate as well including: Energy Assets Networks and Pipelines, GTC Infrastructure, and Vattenfall Heat as well as other telcos like Community Fibre. The 33 local authorities of London own and operate their own highways assets like streetlights, gullies, SUDS among other assets. Finally, the non-utility/non-local authority group includes asset owners such as TfL, Historic England, Environment Agency along with those building major infrastructure works like Tideway and HS2.

NUAR’s progress in London would not have been possible without the support of this diverse underground asset owner community. The benefits of NUAR have been clear to them from the start and this type of platform has been wanted within the community for decades.

It has been particularly inspiring seeing all 33 local authorities of London participating in NUAR even though recent years have often seen shrinking data resources for boroughs. From the NUAR pilot in 2019 to today, we have not lost a single asset owner in London which demonstrates the effectiveness of our engagement with the London community and that the community can see the benefits that NUAR will have for them once live.

Key learning — the importance of collaboration

We cannot underestimate the importance of collaboration and engagement. Collaboration has been a pillar of the NUAR programme’s ethos and the delivery team has heavily relied on underground asset owners’ feedback as the programme developed from a pilot to an MVP product and will continue to develop into an operational platform in the future.

There has been a mutual understanding between all asset owners that by providing feedback, they would help shape the future development of the platform. Only by truly listening to our partners and understanding their current processes on accessing and sharing underground asset data can we build a system that will ultimately fulfil the key use cases of safety and efficiency. Listening to the concerns of asset owners who may be at varying stages of technological and organisational maturity around data sharing was an important aspect to engagement as well.

NUAR’s role as part of the Mayor’s priorities

NUAR closely aligns with the Mayor’s 2021 Manifesto commitment to harness data and emerging technologies for our city as part of our Data for London (DfL) programme. A central principle of this programme is to ensure London is a leading city in the responsible use of data to create useful products, services and new value. Building a digital twin of our underground landscape including sensitive assets inevitably raises questions around how we ensure this data doesn’t end up in the wrong hands. Since the pilot, the NUAR team has led with a security minded approach working closely with the National Protective Security Authority (NPSA) as well as the National Cyber Security Centre (NCSC) to ensure we continue to take all precautions we can to keep data safe.

NUAR also contributes to the Connected City pillar of London’s Economic Recovery Framework by minimising road network disruption and is also expected to reduce infrastructure project delivery issues and related costs. Utility strike avoidance and onsite efficiency will mean fewer delays and road closures while excavating on London roads. Once NUAR is launched it should be​ a​ supporting tool for the GLA’s Infrastructure Coordination Service (ICS), and we are exploring with the Geospatial Commission the potential expan​sion of​ NUAR’s use cases to include infrastructure coordination.

Looking ahead

The Geospatial Commission will continue to publish updates on future roll out of NUAR to other regions of England here. We’ve been delighted to be part of this project from the beginning of the pilot and have worked closely with the wider NUAR team throughout, with a strong ‘one team’ approach. NUAR is envisaged to be fully operational across England, Wales and Northern Ireland in 2024​/25​ and City Hall will continue to work with the NUAR team to prepare for the operational launch.



Chief Digital Officer for London

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