Meet the team

Professors Cath Mercer and Pam Sonnenberg lead the Natsal study from UCL as joint Principal Investigators.

Read below to find out more about the study's leadership team and their different areas of work within Natsal, as well as their other research experience. 

Cath and Pam in front of Natsal sign
Cath Mercer
Professor Cath Mercer, UCL

A statistician and demographer by training, Professor Cath Mercer is Co-Principal Investigator for Natsal-4 and the Natsal Resource, with Professor Pam Sonnenberg. Since 2000, Cath has played an instrumental role in the Natsal studies, having previously led the statistical analyses for Natsal-2 and Natsal-3 and overseen the delivery of Natsal-3 with Pam. Cath’s expertise lies in developing and employing robust methods that advance the scientific study of sexual behaviour and generate evidence that impacts sexual health policy and practice for minority groups through to the general population. Cath is also passionate about public engagement, ensuring the impacts of her research benefit the people with whom it is undertaken, as well as the general public more broadly.

Professor Pam
Professor Pam Sonnenberg, UCL

Professor Pam Sonnenberg is a clinically-trained academic in public health and infectious disease epidemiology and is Co-Principal Investigator for Natsal-4 and the Natsal Resource, with Professor Cath Mercer. Pam led the STI work package for Natsal-3 as well as overseeing research governance, budget and contracts. Pam is well–recognised for leading multi-disciplinary teams that produce innovative research that has clinical, public health and policy relevance; links behaviour and biology; spans developed and developing countries; and is both methodological and applied.


Professor Rob Aldridge, UCL

Rob Aldridge

Rob is a Professor of Public Health Data Science and Wellcome Trust Clinical  Research Career Development Fellow in UCL's Institute of Health Informatics. Rob's research aims to equitably improve the health of the public through the  application of data science and public health research. He leads on the data  linkage work for Natsal-4. Taking a less typical route to public health research,  Rob studied Mechanical Engineering and worked in management consultancy  before qualifying in medicine from UCL in 2007. He then went on to do an MSc  in Epidemiology at London School of Hygiene & Tropical Medicine (LSHTM) and  completed his PhD in infectious disease epidemiology at UCL. Rob is also Chief  Investigator for the Virus Watch equity study and has undertaken a range of  analyses to inform the public health response to the COVID-19 pandemic.

Professor Chris Bonell, LSHTM

Chris Bonell

Chris is Professor of Public Health Sociology at the London School of Hygiene & Tropical Medicine (LSHTM). Prior to this, he has had Professorship roles at UCL and the University of Oxford and has been a Research Team Leader in the UK government’s Social Exclusion Unit. His main areas of research are on adolescent health, sexual health and evaluation methodology. His research on adolescent health focuses on how schools and school-based interventions can benefit or harm young people’s health and his research on sexual health examines the broader social factors of adolescent sexual health behaviours and outcomes, and interventions to address these. He is a NIHR Senior Investigator and a participant on various SAGE subcommittees advising government on COVID-19.

Soazig Clifton, NatCen


Soazig is a survey methodologist and epidemiologist, and as Natsal’s Academic Director, has a joint post with UCL and NatCen Social Research. She has >15 years’ experience in the design, delivery, analysis, publication and dissemination of large-scale general population health research, with a focus on sexual behaviour and sexual health in Britain. Soazig joined the Natsal team in 2008 to work on Natsal-3 and has since overseen the questionnaire development and testing, and survey implementation.

Professor Andrew Copas, UCL

andrew copas

Andrew is a statistician jointly in UCL's Institute for Global Health and the MRC Clinical Trials Unit, and he provides statistical oversight for Natsal. He is Director of the Centre for Pragmatic Global Health Trials and his main research interest is in the design of cluster randomised trials. He has contributed to the design and analysis of earlier Natsal surveys, and several other important studies in infectious disease epidemiology including FluWatch. He is involved in three major ongoing COVID-19 research studies: the VIVALDI study in British care homes, Viruswatch, and the COG-HOCI study of hospital acquired infection.

Professor Nigel Field, UCL

Nigel Field

Nigel joined the Natsal team in 2008, and now leads the STI testing and the Biobank Resource for Natsal-4. He is an Associate Clinical Professor within the UCL Institute for Global Health where he is Director of the Centre for Molecular Epidemiology and Translational Research. He is Co-Principal Investigator with Professor Kirstin Mitchell on the Natsal COVID study.

Dr Jo Gibbs, UCL

Jo Gibbs

Jo is a Senior Clinical Research Associate in UCL's Institute for Global Health at UCL and an Honorary Consultant in Sexual Health & HIV at Mortimer Market Centre. Her research interests include digital health, developing and evaluating complex interventions, health service delivery and public health. Her current research focus is on the development and evaluation of online clinical care pathways from diagnostics to online management of STIs and HIV, understanding the complex legislation and regulation in this area, and the impact of remote  service delivery on health inequalities. 

Dr Wendy Macdowall, LSHTM


Wendy is an Associate Professor at the London School of Hygiene & Tropical Medicine (LSHTM) and has worked on the second and third Natsal surveys. Her experience includes research into the determinants of sexual health, the development of interventions to improve and promote sexual health and the evaluation of public health interventions.  Wendy works on the NIHR Policy Research Programme Reviews Facility, which supports national policy development and evaluation and she is also a Programme Director for the MSc in Public Health at LSHTM.

Professor Kirstin Mitchell, University of Glasgow

Kirstin Mitchell

Kirstin is Professor of Social Science and Public Health in the Institute for Health and Wellbeing at the University of Glasgow. She is an inter-disciplinary social scientist focused on intimate relationships and health. She is the Natsal study site-lead for University of Glasgow as well as leading on qualitative research across the Natsal study. On the Natsal-4 survey she leads on modules focused on sexual attitudes, sexual function and sexual wellbeing, including the development of the Natsal Sexual Wellbeing measure, having previously led the development of the Natsal-SF (sexual function measure). She is also Co-Principal Investigator (with Dr Nigel Field) on the Natsal-COVID study.

Gillian Prior, NatCen


As Director of Surveys, Data and Analysis at NatCen, Gillian leads a team of around 80 researchers, data specialists and analysts, covering household, longitudinal and health & biomedical surveys, health and social care policy research and ScotCen. Gillian oversees the design and management of NatCen’s portfolio of social surveys in a wide range of policy areas, including Natsal.

Gillian has spent her career in applied social research and has over 25 years’ experience of managing social surveys and leading research teams. She is a Fellow of the Academy of Social Sciences and a trustee of the Social Research Association.

Dr Clare Tanton, LSHTM

Clare photo

Clare is an Epidemiologist with an interest in adolescence and expertise in sexual and reproductive health and violence against children. She has worked on large-scale surveys and school-based interventions and her research has been both in the UK and overseas. She is currently working on trials of school-based interventions to reduce violence in schools and to improve menstrual health management in Uganda. Clare has been an integral part of the Natsal team since 2008 and now leads on the sexual violence module for Natsal-4.

Professor Magnus Unemo, Örebro University


Based in Sweden, Magnus directs the WHO Collaborating Centre for Gonorrhoea and other STIs, and the Swedish Reference Laboratory for Sexually Transmitted Infections, Örebro University Hospital. His main research focuses on Neisseria gonorrhoeae and other bacterial STIs. He joined the Natsal-4 team to advise on the development and delivery of Natsal's STI testing and Biobank Resource.

Professor Nicholas Thomson, Wellcome Sanger Institute

You can find out more about Nick's work here.