Footnotes

• Twitter @thebiledoc@djosh78, @drmwjames, @GWebster_endo

• Contributors WA wrote and prepared the manuscript. DJ, MTH, SME, MJ, SM, KWO, WO, BP, PT and GW reviewed and corrected the manuscript. VSH supervised, reviewed and edited the manuscript. All authors have read and agreed to the final version of the manuscript.

• 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.

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