Footnotes

• Contributors TAW, RV, CB and RK were each involved in devising and implementing the traffic light system reported. This paper was written by MM and RV with oversight and input from TW and DW.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests None declared.

• Patient consent for publication Not required.

• Provenance and peer review Not commissioned; internally peer reviewed.