The Twentieth Century Society

Campaigning for outstanding buildings


Initially set up entirely by volunteers, the Society now has three full time and two part-time staff based at our London offices, with a wider community of people making vital contributions on a voluntary and freelance basis.


Catherine Croft Director

Catherine has been Director of C20 Society since 2002, and is Editor of the C20 magazine. She works Monday – Friday.

Catherine read Architecture at Cambridge University, and did an MA in Material Culture & Architectural History in the USA, where she held a fellowship at the Winterthur Museum in Delaware. She has lectured to post graduate building conservation students throughout the UK, and is an alumni of the Architectural Association course. Prior to C20 Society she worked for English Heritage as a buildings inspector in London and the Midlands. Author of a book on Concrete Architecture, Catherine writes on contemporary as well as historic buildings, lectures internationally and  teaches a course on concrete for conservation professionals at West Dean College.

Get in touch

  • 020 7250 3857

Coco Whittaker Head of Casework

Coco works full-time and has recently completed a part-time MSt in Building History at Wolfson College, University of Cambridge, specialising in vernacular and 20th-century architecture and writing a thesis on early 20th-century pithead baths in Durham and Northumberland. Her BA was also at Cambridge Uni in History of Art and Architecture.

Get in touch

  • 020 7250 3857

Oli Marshall Campaigns Director

Oli manages the society’s campaigns, press, brand and partnerships. Amassing 10 years experience with British design brands Anglepoise and Tom Dixon Studio, he developed global partnerships and collaborations with the likes of Paul Smith, Margaret Howell and the National Trust.

More recently, he co-founded the successful campaign to revive the historic Crystal Palace Bowl venue (a former Stirling Prize nominee), launching a record-breaking community crowdfunder and securing funding from the Mayor of London. He studied English at the University of Newcastle and has written on product design, urbanism and community activism.

Get in touch

  • 020 7250 3857

Jonathan Woods Operations Manager

Jonathan keeps all the society’s day-to-day activities running as our Operations Manager. With a career that started in mathematics then law and moved on to publishing, he still edits a number of titles for the legal profession. His most recent role before joining C20 was at the Guild of Food Writers where he was the whole staff supporting the management committee on all the Guild’s activities.

Get in touch

  • 020 7250 3857

Honorary Officers and Trustees of the Society

Hugh Pearman Trustee and Chairman

Hugh is a distinguished journalist, editor and author. He was architecture and design critic of The Sunday Times for 30 years (1986-2016), editor of the RIBA Journal for 14 years (2006-20), and has written extensively for other media. His latest book, ‘About Architecture: An Essential Guide in 55 Buildings’ was published by Yale University Press in May 2023.

In addition, Hugh served on Arts Council England’s architecture advisory group, was one of the instigators of The RIBA Stirling Prize for Architecture in 1996 and chaired the “Art for Architecture” initiative at the Royal Society of Arts from 2000-04. He was made an Honorary Fellow of the Royal Institute of British Architects in 2001 and was awarded an MBE for services to architecture in 2019. He became C20 Chairman in August 2023.

Catherine Slessor President

As well as being C20 Society’s President since July 2021,Catherine is currently a Contributing Editor to the Architectural Review and was its Editor between 2010 and 2015. She has written for numerous publications, including the Observer, Guardian, Architects’ Journal, Icon and Dezeen. She studied architecture at the University of Edinburgh and was in private practice for a time before defecting into journalism. She also holds a Masters degree in Architectural History and Theory from the Bartlett School of Architecture, University College London. In 2016 she was awarded an MBE for services to architectural journalism.

Mark Eastment Trustee and Convenor of Publications Sub-Committee

Mark is Editorial Director at Yale University Press, London for Art and Architecture, which includes overall management of the Pevsner revisions and distribution and production of the Survey of London series. His main interests are decorative and mid-century British art. He has a good understanding of the current publishing scene, which should help the Society’s forward publishing programme, maintaining its continued academic excellence while perhaps trying to improve its overall profitability. He also carries out work for Ashmolean Publishing Group, Bodleian Publishing Group, Paul Mellon Publishing Group and Decorative Arts Society.

Carolyn Parmeter Trustee and Honorary Treasurer

Carolyn has been Honorary Treasurer since 2013.  She had a previous stint as a Trustee and Honorary Membership Secretary in the early 2000s.  She has a tax background and is a Senior Civil Servant working in policy at HMRC. Outside work she was a volunteer guide at the National Trust’s 2 Willow Road for over 10 years and for a shorter time at The Homewood.

Peter Ruback Trustee

Peter was C20 Society Chairman from 2012 to 2021. After a short period as a theoretical physicist he was a civil servant working in central government in a variety of transport policy and housing roles mainly concerned with investment, financing, regulation and planning of infrastructure. He is interested in all styles of post-1914 architecture and is passionate about protecting and reducing the threat to buildings that are easily passed over and not widely appreciated. He also chairs the Westminster Tree Trust and the Pimlico Neighbourhood Forum.

Cela Selley Trustee and Honorary Events Secretary

Cela was employed by the Society for 10 years as office co-ordinator, and then developed the role of C20 Volunteering Co-ordinator. She was the Society’s Honorary events Secretary until July 2021.  She is also an elected member of the management team of a successful sports and leisure club, responsible for HR. In 2023 she took on the role of Honorary Events Secretary.

Andrew Jackson Trustee

Andrew studied at Liverpool School of Architecture and the University of Liverpool’s Department of Civic Design and has a particular interest in urbanism. He has worked with a number of museums and galleries, including as ‘urbanist in residence’ in Sheffield, and is a Trustee of Sheffield Design Awards. He was Chair of the C20 Yorkshire group from 2014 until 2019, and the Society’s Regional Groups Coordinator between 2019 and 2023. Andrew is also a Trustee and Director of Civic Voice, which oversees the civic movement in England and the All-Party Parliamentary Group (APPG) for Civic Societies in Westminster. He is currently researching the Preston-based Welsh architect, Francis Roberts.

Jeremy Gostick Trustee and Chair of Audit & Risk sub-Committee

Jeremy trained as an accountant and has spent his career at the National Audit Office, engaged predominantly in work to assess the economy, efficiency and effectiveness with which various  government departments implement government policy – in particular the NHS, Ministry of Defence and government estate.

Jeremy is Chair of the Audit and Risk Committee, with a focus on securing our long term financial future.


Ellen Gates Trustee and Honorary Secretary

Ellen worked as a solicitor, specialising in major infrastructure, transport and energy projects.  Since retirement, she has pursued a lifelong, but amateur, interest in architectural history, with an increasing focus on twentieth century architecture.  Having volunteered for the Society, assisting the Caseworker team, she became Honorary Secretary in mid-2022.

Sarah Jackson Trustee

Sarah has been a registered architect since 1994. After working in architectural practice and teaching history of architecture, she joined CABE, where she was Head of Design Review.  Sarah is currently a townscape and heritage consultant, working on major developments in London.

Dr Alan Powers Trustee

Alan is an architectural historian specialising in British architecture. A founder member of the Thirties Society in 1979, he has filled a number of roles since that time, as caseworker, Honorary Secretary and Chairman. He is joint editor of the Society’s journal, Twentieth Century Architecture, which he founded in 1994, and of the monograph series Twentieth Century Architects. He usually organises the spring and autumn lecture series in London and has led many events.

Otto Saumarez Smith Trustee and Chair of Casework Committee

Otto Saumarez Smith is Assistant Professor in Architectural History at the University of Warwick. He was Shuffrey Junior Research Fellow at Lincoln College Oxford, and received a PhD from the University of Cambridge. His book Boom Cities, Architect Planners and the Politics of Radical Urban Renewal in 1960s Britain is published with Oxford University Press. He co-edited the Volume 11 of the Twentieth Century Society’s Journal on Oxford and Cambridge. He is a Fellow of the Royal Historical Society, and an editor of the Society of Architectural History of Great Britain’s journal Architectural History. He has published on subjects such leisure centres, inner city policy, shopping centres, as well as architectural practices including Gillespie Kidd & Coia, Chamberlin Powell & Bon, Sheppard Robson, Building Design Partnership, Howell, Killick, Partridge and Amis, and Powell and Moya.

Website and publications

James Hunter Art Director, C20 Magazine

Alexa Baracaia Deputy Editor, C20 Magazine

Studio Hunter & Stephen Coates, & Ebow, the digital agency Web design

James Sui Web developer


Position Vacant Volunteer Press Officer

Joe Mathieson Building of the Month Editor

Thaddeus Zupančič Instagram volunteer

Graham Orbell
Casework volunteers

David Thomas Administrative volunteers

Polly Schlesinger
Julie Kenwright
Sarah Lewis
Barry Needoff
Simon Wartnaby
Mark Davies
Events volunteers

Volunteer your talent

Use your spare time and talents to help us as a valued C20 Society volunteer.

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