Designing accessible services for BSL users: key principles

This year marked an important milestone in government digital services. The DVSA theory test booking service became the first government service in the UK to deliver content through British Sign Language (BSL) signed video.

Working in partnership with Signly, a technology company specialising in signed content delivery, Kainos helped introduce BSL-first content for DVSA theory test users. The goal was simple but significant: break down barriers for d/Deaf users experience booking their theory tests independently.

For Kainos, this was more than delivering accessible technology. It was about working closely with the BSL community, listening to, and understanding their lived experiences, and learning how design choices often create barriers where none should exist.

Learning from the BSL community

In the lead-up to launch, our research teams collaborated with Deaf charities, hubs, and BSL speakers across the UK. Through co-design workshops and research sessions, we gained direct insights into the challenges BSL users face when accessing GOV.UK services.

One clear message stood out: for many Deaf users, the barriers come not from disability, but from services being designed primarily for people whose first language is written English.

The research we conducted with the BSL community showed us that we need to go beyond existing accessibility frameworks to meet the basic needs of BSL users accessing digital services. While the GOV.UK Design System has transformed public service design — offering consistency, scalability, and confidence in accessible delivery — it is still rooted in text-heavy, form-based interactions. This works well for many users, but not necessarily for those who think and communicate visually through BSL.

WCAG prioritises vision, but what about d/Deaf users?

Web Content Accessibility Guidelines (WCAG) have informed regulations that ensure digital services are accessible. WCAG prioritises keyboard operability as a baseline, which helps ensure that content and interface designs are compatible with technologies such as screen readers. As a result, these guidelines primarily address the needs of blind or low-vision users.

There is less emphasis on the accessibility needs of d/Deaf users. While some WCAG success criteria encourage the design of simple and clear interfaces, the primary focus remains on supporting blind and low-vision users.

BSL users, in contrast, are visual communicators. Using images, symbols, and icons can provide effective visual cues that help BSL users understand meaning and context more easily. However, this approach is not a central component of the GDS design system. While GDS provides guidance on the use of images, symbols, and icons, the default recommendation is to “avoid using icons in most cases, as a single icon can be interpreted in multiple ways and may therefore cause confusion”. There is certainly room to extend design principles for better utilising imagery for visual users.

Why this matters

In the UK alone, 1 in 6 people are Deaf, deaf, hard of hearing, or affected by tinnitus. That’s around 12 million people today, and is expected to rise to 14 million by 2035. Globally, the World Health Organization (WHO) estimates that over 1.5 billion people live with some level of hearing loss.

For BSL users, written English is often a second language, with its own grammatical structures and complexities that don’t map neatly onto BSL.

Designing services that rely exclusively on text risks leaving these users behind. By embedding BSL-first design patterns into our systems — from video-first content to alternative contact methods — we can reduce barriers, improve equity, and edge digital public services towards being fully accessible.

Understanding Deaf, deaf and Hard of Hearing

Not all users with hearing loss have the same needs.

• deaf (lowercase “d”): people with hearing loss who may use spoken language.
• Deaf (uppercase “D”): members of the Deaf community, a cultural and linguistic minority whose first language is often BSL.
• Hard of Hearing (HOH): people with partial hearing loss, who may use hearing aids, spoken language, or sign language.

These groups are not homogenous. For BSL users in particular, exclusion often comes from design decisions, not disability.

Service design principles for BSL users

Through our research and co-design work with the BSL community, we’ve identified eight key guiding principles to shape better digital services for BSL users.

1. Written English is not BSL users’ main language

Many BSL users read English as a second language, which makes dense text difficult to process. Using plain, direct language is not just a best practice, but essential.

• Keep sentences short and active.
• Replace jargon with simple alternatives.
• Structure content with headings, lists, and spacing to reduce cognitive load.
• Break up long instructions into step-by-step guidance.

This doesn’t just help BSL users . It makes the service easier for everyone.

2. Prioritise BSL-first content by default

Whenever possible, make BSL video the primary way to deliver essential information rather than treating it as an add-on. For example:

• embed signed explainer videos directly into key journeys (e.g. theory test booking confirmation screens)
• use signed instructions for complex or high-stakes tasks, like payments or application forms
• always include subtitles with BSL-video content so users can connect signs with written words

This approach shows Deaf users that their language is not an afterthought, but a core part of the service.

3. Don’t rely on written text alone

BSL is a visual-spatial language. Users understand context better when supported by visual prompts, such as:

• icons that consistently represent actions (for example, a calendar icon for bookings)
• colour-coded themes to help distinguish sections or functions
• step diagrams or flowcharts to explain processes visually

This is not decoration. It is critical to communication. For BSL users, meaning is often carried more effectively through visual reinforcement than through additional text.

4. Provide Deaf-friendly contact methods

Asking for a telephone number assumes the ability to use voice calls. For BSL users, this is often impossible. Better alternatives include:

• Video Relay Service (VRS): allows a Deaf user to sign to an interpreter, who relays the conversation by phone
• videophone chat: a direct video call using BSL
• text-only systems: SMS updates or web chat for simple interactions

When a service defaults to “phone only,” it immediately excludes a large group of users. Building inclusive contact channels makes access equal.

5. Avoid open-ended questions

Free text boxes can be particularly challenging for BSL users. Explaining in written English what information is required often creates additional barriers, as it may not align with how BSL users naturally communicate.

Better approaches include:

• replacing open text with multiple-choice or yes/no options
• using checkboxes, radio buttons, or dropdown menus for clarity
• if free text is unavoidable, provide very clear prompts and examples of what’s expected

This removes unnecessary barriers and gives users confidence they are answering correctly.

6. Make accessing support simple and visible

Support should not feel like a detour. For BSL users, being forced to leave the main task to hunt for help creates confusion and increases drop-out rates. Instead:

• place support options directly within the journey, not hidden in a footer
• use “sticky” help icons or embedded video support to keep users on-task
• offer BSL video support where possible, especially for complex processes

The principle is simple: users should be able to complete their task without leaving the page they’re on.

7. Use simple layouts

d/Deaf users can experience eye strain from the sustained visual focus needed for lip-reading or watching sign language. Simple, well-structured layouts reduce effort and improve comprehension.

• Use single-column layouts to structure content
• Present instructions step by step, with one action per line or stage
• Use visual sequencing (numbered steps, diagrams, flowcharts) instead of long paragraphs
• Avoid implied references like “see above” or “as noted earlier,” which disrupt understanding

8. Colour matters

BSL users rely on visual cues, and colour provides an immediate way to convey meaning and guide navigation. It reduces cognitive load and helps users move through tasks more quickly.

• Use colour to signal key information: errors (red), success (green), warnings (yellow)
• Differentiate pathways or options with consistent colour coding
• Apply colour consistently to orient users in the interface (for example, action buttons vs. navigation)
• Pair colour with icons or text so meaning isn’t lost for colour-blind users

Closing thoughts

The launch of BSL-first content for the DVSA theory test shows what’s possible when we move beyond compliance and design digital services around peoples lived experiences.

Our work with the BSL community made it clear: accessibility is not about adding features at the end, but about rethinking design choices from the start. More importantly, involving communities of users who face barriers to accessing services in the design process is essential to truly understanding their needs and creating solutions that work for them.

The principles we’ve outlined highlight that BSL users need services built with visual-first communication, simple layouts, and inclusive contact methods, not services that assume written English or phone calls as the default. These are not just “nice to haves”; they are essential to equity.

By embracing these principles, we can build upon the GOV.UK Design System in ways that make it more inclusive, responsive, and representative of all users. This is not about creating a parallel experience for Deaf people, but about designing public services that reflect the diversity of how people communicate and navigate the world.

Accessibility is an ongoing practice. If we continue to learn directly from BSL users, we can shift from designing services that are merely accessible to services that are truly inclusive.