The system

The team

Ermine is built by a federated team drawn from across Style Weasel Productions. Federated means that everyone contributes and nobody is assigned.

Model Federated Last reviewed 4.0.0 · November 2025 Owner Design Systems Engineering

Accountable for Ermine

Wilhelmina Notwithstanding

Head of Design Systems Enablement

Authored all six of Ermine's design principles and continues to steward them across the portfolio.

Believes a design system is a product, not a project, and says so at least once per quarterly review.

Barnaby Quorum

Principal Design Technologist, Tokens & Taxonomy

Custodian of Ermine's single source of truth. Maintains ermine-tokens.css personally, by hand, which he describes as a temporary arrangement.

He has described it as a temporary arrangement since March 2025.

Persimmon Runway

Director of Adoption & Ecosystem Velocity

Grew product-team adoption from 11% to 94.7% in a single quarter — the fastest adoption curve in the system's history — through a programme of enablement, evangelism, and close partnership with Platform Engineering.

Runs monthly Ermine Office Hours. Attendance is tracked.

Egret Blancmange

Staff UX Researcher, Design Systems (0.2 FTE)

Embedded across all fourteen product teams. Owns the evidence base behind every Ermine pattern and is the strongest internal advocate for Principle 5, Evidence-led.

Available Thursdays.

Marzipan Sledge

Senior Manager, Component Enablement & Stakeholder Choreography

Convenes the Design Systems Council fortnightly and is accountable for its minutes.

Has published two sets of minutes in the past fourteen months.

Thaddeus Whelk

Chief Experience Officer & Executive Sponsor

Sponsors Ermine at board level. Championed the identity refresh that became Ermine 4.0, following a competitive review conducted between connecting flights, and describes Ermine as the most significant thing the design organisation has shipped.

Has requested one change to the system.

Ermine has three contributors. Six people are accountable for it.

Open roles

RoleStatus
Head of Content DesignVacant since March. Voice & tone is unowned.
Design Operations LeadVacant since March. Figma write access and the open-issues spreadsheet sit with this role.
Design Systems Council ChairRotating. The rotation is paused.
Data Visualisation, Design SystemsRealigned in 4.2.0. Twelve components moved to Community Maintained.

These responsibilities are currently covered by Design Systems Engineering.

How we work

Design Systems CouncilFortnightly, quorum permitting.
Ermine Office HoursMonthly. Open to all. Attendance is tracked.
Quarterly portfolio reviewWhere RFC sponsorship is granted.
Annual roadmap workshopWhere major-version slots are allocated.
#ds-quick-questionsWhere the work happens. Deprecated.

Where Ermine came from

Ermine began in 2022 as a shared Figma file assembled by a product designer on the Billing team, who was tired of rebuilding the same four components every sprint. That file is the Ermine Figma library, and it remains the source of truth for design across the portfolio.

The designer who created it moved to another team during the platform migration and does not have write access.