The Society of London Theatre
http://www.solt.co.uk

Bectu
http://www.bectu.org.uk

Creative and Cultural Skills
http://ccskills.org.uk

UK Theatre
http://www.uktheatre.org

Musicians' Union
http://www.musiciansunion.org.uk

The Theatre Trust
http://www.theatrestrust.org.uk

Masterclass
http://www.masterclass.org.uk

Theatre Craft
http://www.theatrecraft.org

League of Independent Producers
https://leagueofindependentproducers.com

Equity
http://www.equity.org.uk

Arts Council
http://www.artscouncil.org.uk/

Official London Theatre
http://www.officiallondontheatre.co.uk

The Stage
http://www.thestage.co.uk

Stage Sight
https://www.stagesight.org

Function Central - Guide to Supporting the Mental Health & Wellbeing of Musicians
https://www.functioncentral.co.uk/mental-health/