About TetraLogical

We’re a boutique company, with lots of experience and a whole new attitude.

We formed TetraLogical in 2019 because we saw the market become more driven by legal compliance than meeting the needs of different people. Compliance is important but it doesn’t guarantee inclusion, so we bridge the gap between the two in intelligent ways tailored just for you.

We like new ideas and finding pragmatic solutions to complex problems. We know that inclusion takes many forms, so our services encompass knowledge, experience, strategy, assessments, and development.

Our vision and principles

We believe in a world where technology holds no one back.

We put people first: you and your customers, our partners and employees, and everyone we meet. TetraLogical is founded on four principles that mean everything we do is:

  • Inclusive: we consider everyone and make decisions that exclude no-one
  • Sustainable: we work collaboratively and efficiently to amplify enduring accessibility
  • Ethical: we make decisions for the good of our customers and their customers, our people, and for the world at large
  • Original: we like new ideas and finding simple solutions to complex problems

As part of our work on accessible experiences within Extended Reality (XR), we've created a 3D TetraLogical principles cube.

Our people

Every member of our team has more than 10 years’ experience in the technology industry; we’ve all been involved in accessibility since its earliest days on the web.

Léonie Watson

Léonie is a Director at TetraLogical. She also sits on the Board of Directors for the W3C, and is co-Chair of the W3C Web Applications working group.

With more than 25 years’ experience working for organisations including Nomensa, The Paciello Group, and Government Digital Service, Léonie is a respected member of the web community. Naturally hard-working and organised, she has spent time managing complex web projects, as well as working in her habitual capacity as accessibility engineer. In 2018, Microsoft recognised her contribution to the field of accessibility by making her one of the first Most Valued Professionals (MVP) outside of the Microsoft community. She was a co-author of the Inclusive Design Principles, and more recently co-authored the Do No Harm Guide: Centering accessibility in data visualization.

Léonie Watson

Ian Pouncey

Ian is a Director at TetraLogical, a member of a number of W3C working groups, and a web developer with more than 20 year’s experience.

Ian worked as a web developer for companies including Yahoo!, Bloomberg, and the BBC before becoming a full-time accessibility specialist in 2013. He worked as a Senior Accessibility Specialist as part of the BBC’s digital UX division and later joined The Paciello Group as a Senior Accessibility Specialist and User Experience Development Lead.


Henny Swan

Henny is a Director at TetraLogical and a user experience and design accessibility specialist with over 20 years' experience.

Formerly at the BBC, The Paciello Group, Opera Software, and RNIB, Henny was co-author of the Inclusive Design Principles and lead author of the BBC Mobile Accessibility Guidelines. She's particularly happy helping teams and companies make accessibility a seamless part of what they do.

Henny is a graduate of the Goldman Sachs 10,000 Small Businesses programme, a member of Group of Humans, and a regular speaker at conferences.

Henny Swan

Steve Faulkner

Steve is a Director at TetraLogical with over 20 years of experience specialising in screen reader accessibility, Accessible Rich Internet Applications (ARIA), and HTML5.

Previously, Steve was the Chief Accessibility Officer at TPGi and a Senior Web Accessibility Consultant at Vision Australia. He is a member of several groups, including the W3C Accessibility Guidelines Working Group and ARIA Working Group. He has been an editor of several specifications at the W3C, including HTML5, ARIA in HTML, and HTML Accessibility API Mappings 1.0. He also writes on HTML5accessibility and supports Freedom Scientific in improve HTML and ARIA support in the JAWS screen reader.

Steve Faulkner

Patrick H. Lauke

Patrick is Principal Accessibility Specialist, Assessments at TetraLogical. In a previous life, he was a Principal Accessibility Engineer at The Paciello Group, and before that worked as Web Evangelist in the Developer Relations team at Opera Software.

He’s been involved in the discourse around Web Standards and Accessibility since 2001, actively speaking at conferences and participating in early initiatives such as the Web Standards Project (WaSP).

He is a member and active contributor in the Web Content Accessibility Guidelines working group. He also chairs the W3C Pointer Events working group, and is co-editor of the ARIA in HTML and W3C Touch Events Level 2 specifications.

Patrick H. Lauke

Alistair Duggin

Alistair is Principal Accessibility Specialist, Consultancy at TetraLogical. He is the former Head of Accessibility at Government Digital Service where he transformed how the UK government approached accessibility by embedding accessibility in the GOV.UK Service Manual and Design System, building and supporting a 1000+ strong cross-government accessibility community, and creating the UK's first assistive technology device/empathy lab.

Alistair has over 20 years of digital and accessibility experience, starting as a web developer at the BBC, where he learned how to build accessible websites and grow and support an accessibility community. His approach to accessibility during the creation of the BBC 2012 Olympics website inspired the creation of the BBC Accessibility Champion Network. Other roles include being an Accessibility Engineer at Apple and Principal Accessibility Consultant at Nomensa.

Alistair Duggin

Graeme Coleman

Graeme is Principal Accessibility Specialist at TetraLogical. He has an in-depth understanding of technical accessibility and how to apply the guidelines across web and mobile platforms such as iOS and Android.

Previously, Graeme was a senior accessibility engineer at The Paciello Group and, prior to that, a researcher at the University of Dundee, where he was awarded his PhD in 2008. Graeme has over 15 years of experience performing accessibility assessments of websites and applications on behalf of commercial and academic organisations.

Graeme Coleman

Gez Lemon

Gez is Principal Accessibility Specialist at TetraLogical. He graduated from the University of Surrey in 1997 with a BSc (Hons) in Computing and previously worked at TPGi as a Principal Accessibility Engineer.

Gez has been at the heart and centre of the accessibility community for over 20 years and is well known for articles and tools published on his website Juicy Studio. His main area of expertise is WAI-ARIA, working on complex applications, and helping teams implement accessibility in a way that helps them embed permanently into their practice.

Gez Lemon

Felicity Miners-Jones

Felicity is a Senior Project Manager at TetraLogical. She has over nine years’ experience in management consultancy, working for companies such as Breakthrough Global running projects and productions with a heavy focus on web-based training for customers dispersed across the globe.

Felicity is a communication and behavioural learning specialist, comfortable working in a range of settings to provide intensive communication skills training, one to one coaching, seminar facilitation, and specialist mental health training. She has a creative background and previously founded and ran her own theatre company where she created and delivered a wide range of productions, workshops, and fundraising events. She also has experience working in the care sector, including domiciliary and hospice support.

Felicity Miners-Jones

Dean Holden

Dean is a Senior Accessibility Specialist at TetraLogical. With over 15 years’ experience as a Web Developer at Nationwide Building Society Dean became an accessibility specialist within the organisation and helped our very own Léonie Watson set up the foundations of a dedicated accessibility team.

Together the Nationwide accessibility team began work to embed accessibility through the company's end-to-end processes, creating role-specific guidance on accessibility responsibilities and delivering face-to-face team training sessions.

More recently, Dean has worked as a Senior Accessibility Engineer at TPGi, leading a team in providing accessibility audits for customers.

Dean Holden

Joe Lamyman

Joe is an Accessibility Specialist at TetraLogical. He has worked across different sectors to create usable and accessible digital experiences.

Previously, Joe worked within Defra’s accessibility team to help public sector bodies deliver services that are as accessible to as many people as possible. He also has experience developing accessible design systems and patterns as part of an MSc by Research degree and from working with universities in the UK and Australia, during his time with SkillsForge.

Joe Lamyman

Demelza Feltham

Demelza is an Accessibility Specialist at TetraLogical. Prior to joining, Demelza worked as an Accessibility Analyst at User Vision within their digital accessibility team. Demelza has experience working across multiple sectors, regularly conducting accessibility audits, supporting user research initiatives, and co-running empathy labs.

Demelza holds an undergraduate degree in Anthropology and Philosophy, complemented by a Master of Science in Religious Studies. Additionally, she has earned a UX diploma, further solidifying her understanding of human centred design principles.

Demelza Feltham

Our community

We dedicate some of our time to supporting knowledge share in the technology community. This includes contributing to community projects, conferences, and mentoring schemes.

World Wide Web Consortium

We’re members of the W3C, with Léonie Watson elected to the first W3C Board of Directors. A number of the TetraLogical team contribute to standards like the Web Content Accessibility Guidelines (WCAG) and Accessible Rich Internet Applications (ARIA) as well as the Immersive Web Working Group, so we put a rare level of technical knowledge at your disposal.

Inclusive Design 24

Inclusive Design 24 (#id24) is a free 24-hour online event for the global community. It celebrates inclusive design and shares knowledge and ideas from analogue to digital, from design to development, from planners to practitioners, and everything and everyone in between.

Inclusive Design Principles

The Inclusive Design Principles are designed to give anyone involved in the design and development of websites and applications - designers, user experience professionals, developers, product owners, idea makers, innovators, artists and thinkers - a broad approach to inclusive design.

TetraLogical User Experience Network

Our User Experience Network is a group of people who use assistive technologies, alternative input devices, and other accessibility services. They provide valuable feedback about their experiences using products and services as part of our agile usability testing and usability testing services.

Contact us

We like to listen. If you have a project, product, problem, or idea that you want to discuss, get in touch!