From Tuesday, 22nd September 2026, West Yorkshire will be switching from the current traffic light classification (TLC) system to work in line with Single National Formulary (SNF) categories as West Yorkshire are an early adopter of this work.

The SNF was announced as part of the 10-year health plan in summer 2025 and aims to reduce bureaucracy and inconsistencies while improving patient access to medicines.

The first step is to agree and roll out national medicines categories and language around medicines access. You can read more about the SNF on NHS England's website. 

This first step is simply a change in language and will not result in any change in practice.

Please see the table below, or the SNF classification summery table document, for how these new categories map across to our current WY traffic light classifications.

West Yorkshire Net Formulary

These new SNF categories will be appearing on all existing Net formularies from 22nd - 23rd September 2026. Currently each acute trust hosts a separate Net formulary. This leads to duplication of work, additional use of resources, and inconsistency across West Yorkshire. 

From September 2026, there are teams working across West Yorkshire to combine each of the Net formularies onto a single site to allow for consistent, clear medicine prescribing across the area. Initially, the Leeds formulary will be updated to reflect the West Yorkshire position, and each of the other formularies will deactivate each chapter as they are reviewed and manually direct users to the Leeds formulary as the work progresses.

Once all the chapters have been reviewed, we will switch onto the new West Yorkshire joint formulary, expected to be completed summer 2028. Monographs where the category for the medicines use requires harmonisation, will be subject to consultation and agreed through WYICS Area Prescribing Committee (WYICSAPC). Please see the Process for Monograph Review flowchart for how this work will take place.

For any questions, please email Janet.Haigh@cht.nhs.uk.