Read the latest news, blogs and reports from the UK LLC and across the longitudinal population data community.


The UK LLC Origin Story

By Robin Flaig, UK LLC Deputy Director

1st Apr 2022

The UK Longitudinal Linkage Collaboration (UK LLC) is a national resource for COVID-19 research. It’s a new and globally unique Trusted Research Environment (TRE) that offers predictable and efficient access to longitudinal data for researchers and analysts across the UK. Through a single application the UK LLC TRE offers pre-pandemic and pandemic data from more than 20 longitudinal population studies linked with health data.   

These data are provided by over 200,000 participants who volunteer to be part of their studies. This work wouldn’t be possible without their participation and willingness to offer insights into many aspects of their lives for the benefit of others. The studies retain control of who can access their participants’ linked data and all permissions set by participants remain in place. 

Robin Flaig, Deputy Director of the UK LLC, talks us through how the idea for this new resource has been bubbling for many years and how the coronavirus pandemic accelerated its development.

The idea for what would eventually become the UK Longitudinal Linkage Collaboration (UK LLC) that we have today was something that has been talked about for over a decade across the longitudinal research community.  

“There must be a simpler way to link data”  

“There must be a quicker way to link data” 

“There must be a more efficient way to link data” 

I worked for UK Biobank for 7 years running their linkage programme. What became clear is that linking data is hard but is absolutely crucial for participant follow up in longitudinal studies and helping ensure those harder-to-reach can be included. It was clear to me that this was a problem that needed solving. At the same time, Andy Boyd – now UK LLC Director, who was then leading the Data Linkage Team at ALSPAC (Avon Longitudinal Study of Parents and Children) and leading on data linkage at CLOSER – was facing the same sorts of challenges. He led work with Garry Coleman (then Service Director of Data Dissemination at NHS Digital) on how to create a solution for studies in relation to onward sharing of linked data. I attended a meeting where this was discussed and Andy and I had many more discussions around the challenges of data linkage, in particular the challenges of linking to GP data.  

The longitudinal research community had often talked about the complexities involved in being able to link study participants data so while the pandemic certainly resulted in this infrastructure being put in place urgently, the need for a more efficient and effective way was identified much earlier. 

As a result of these ongoing discussions there was a theoretical plan for how this new, efficient, effective and innovative piece of infrastructure could be created.  

At the start of the pandemic, the longitudinal research community realised they had an important role to play by asking their study participants how the pandemic was affecting them. At this point in time, I had moved to work as Chief Operations Officer of Generation Scotland. Mary De Silva (then Head of the Longitudinal Research Strategy at Wellcome Trust) asked Generation Scotland and ALSPAC to lead the development of a COVID-19 questionnaire and as part of this funding she asked Andy and I to develop a substantive proposal to create the concept for the UK LLC. This was done in collaboration with the studies, with whom we were already collaborating on the work around the questionnaire development. This funding provided us with a part-time researcher, Jazz Croft to help us get our plan off the ground. 

Mary had been working with MRC/ESRC on an initiative called ‘Population Research UK’ which is being designed to develop more effective and joined up ways of working across the longitudinal research community. 

We undertook discussions with many key individuals across the UK longitudinal population community.  We named this group the ‘Vanguard’, leading the way on bringing all the necessary expertise together to build this new piece of infrastructure and lay out our vision for the road ahead. In a very short space of time, this group co-designed the protocol, agreed our name and put the building blocks in place to create the UK Longitudinal Linkage Collaboration. The first Vanguard members included Andy and myself representing ALSPAC and Generation Scotland and representatives from 1970 BCS, Born in Bradford, ELSA, EXCEED, GLAD, Millennium Cohort Study, NCDS58, Next Steps, NSHD46, SABRE, TwinsUK and Understanding Society.  We all reached out to key individuals to consult on what considerations were critical to successfully build a safe and secure Trusted Research Environment housing study data that linked to other types of data. This brought in expertise from those developing systems for sharing NHS data, such as David Ford from the SAIL Databank, Garry Coleman from NHS Digital and both Cathie Sudlow and David Seymour from HDR UK. 

Their input, guidance and support was critical for this collaboration to have any chance of success. I’m delighted to say that the desire and motivation from studies was strong, and we believed we had a strong and viable proposition to build the UK LLC. 

As the pandemic continued to take hold and its severity became evident. The country looked to science for answers. One of the many calls that our country’s scientists answered was to set up the National Core Studies – at the request of Sir Patrick Vallance, the government’s Chief Scientific Adviser. Six National Core Studies (NCS) were established in response to the coronavirus pandemic including the COVID-19 Longitudinal Health and Wellbeing NCS – where the UK LLC now is embedded. 

This idea that we’d talked about for more than a decade could now be a critical part of building a new research resource to help scientists and policy makers respond to the pandemic. And to make sure our preparedness for future pandemics, was as robust, flexible and responsive as possible. And to create a resource that can be used for other purposes too, including climate change, impacts of financial uncertainty and a myriad of other potential uses. 

Our application to be part of the Longitudinal Health and Wellbeing NCS was funded in October 2020 for an initial period of 6 months to see if we could put the infrastructure in place. This study has six other research themes in addition to the UK LLC. These are healthcare disruption; mental health; society and health; vaccination; serology and long-Covid and you can read more about the impact of this work on their website:

So this really was happening! After an incredibly intense period of time getting to this point we now had the green light to set up a brand new way of working. Challenging at the best of times but like the rest of the country, delivering this work in the midst of a pandemic was truly daunting. However, Andy and I had a clear plan and set about building a team who could help us achieve our goals. Time for a deep breath. 

We have a series of blogs written by our team on their own experiences of joining the UK LLC and using their expertise to build our infrastructure.  Look out for these on the UK LLC website to hear more about our story. 


Andy and I would like to thank the following people for their contributions to the creation of the UK LLC: 

UK LLC Vanguard Group, David Seymour, David Ford, Cathie Sudlow, Martin Tobin, Mary De Silva, John McLeod, Jonathan Sterne, Nish Chaturvedi, Nic Timpson, David Porteous, Garry Coleman. 

 About the UK Longitudinal Linkage Collaboration:  

  • A new way of working for record linkage in longitudinal research. 
  • A four-nations and interdisciplinary infrastructure for secure cross-cohort analysis – with regularly refreshed linkages of COVID-19-relevant health records (geo-spatial linkages underway, administrative data linkages planned for the future) 
  • Aligning complex and divergent governance frameworks into a streamlined and predictable linkage/access route for researchers studying COVID-19 as a disease and the impacts of the pandemic. 
  • Developing a sustainable data science infrastructure that is inclusive of the wider UK LPS community, is responsive to emerging demands, and can inform crisis management and policy maker requirements.