The list of supporters includes:
- Barnsley Labour Left – Facebook
- Birkenhead Left Caucus
- Brighton and Hove Labour Left Alliance – Facebook
- Bristol and West Left Alliance – Facebook
- Bromley Momentum – Facebook
- Cambridgeshire Labour Left
- Camden Momentum – Facebook
- Cheltenham Labour Left – Email
- Croydon Labour Left Alliance – Facebook group
- Cumbria Labour Left Alliance
- Doncaster Labour Left
- Dulwich Labour Left
- Durham Labour Left
- Gravesham Momentum – Facebook
- Halton & Weaver Vale Momentum – Facebook
- Hants Labour Left
- Isle of Wight Labour Left
- Kent Left
- Labour Against the Witchhunt – email, website, Facebook, Twitter
- Labour Party Marxists – Facebook
- Labour4Clause4 – website, Facebook, Twitter, email
- Leicester Labour Left
- Lincolnshire Labour Left
- London Labour Left Alliance
- Merseyside Labour Left Alliance – Facebook, email
- Newham Momentum – Facebook
- North Kent (& Medway) Labour Left
- Northants Labour Left
- Northern Ireland Labour Left Alliance – Facebook
- Nottingham & Nottinghamshire Labour Left Alliance – email, Facebook, Twitter
- Plymouth & Region Left Alliance – Facebook group
- Rossendale Momentum – email
- Rotherham Labour Left – Facebook, email
- Scotland Labour Left
- Sheffield Labour Left – email, website, Facebook, Twitter
- South Tyneside Labour Left (formerly Momentum South Tyneside)
- Swansea Labour Left
- West Midlands Labour Left Alliance – email
- West Yorkshire Labour Left Alliance
- Workers International Network (WIN) – Facebook, Website
- York LRC – email, Facebook, Twitter
- Tosh McDonald, former president Aslef, Doncaster councillor
- Asa Winstanley, journalist
- Jackie Walker
- Graham Bash
- Chris Williamson
- Professor Moshe Machover
- John Dunn, Orgreave Truth and Justice Campaign
…. and over 2,400 individual supporters from over 500 CLPs (as of 25 March 2021)