One of the greatest threats to free speech in Britain is the routine labelling, by the police, of non-violent protests and campaigns as “domestic extremism”. This term has no clear legal definition but is used to justify intensive surveillance and the retention of information on people who in many cases have never been arrested.

Designating a campaign as extremist means everyone associated with it may also find themselves labelled in this way, even if they do nothing unlawful. From anti-fracking and anti-racist campaigners to peace and anti-nuclear groups, international solidarity activists and opponents of hunting, so many people who are legitimately protesting are also subjectively targeted by sweeping terrorism powers. This includes the draconian “counter-radicalisation” Prevent programme, which has been used to try to stifle the political views of young people, their parents and those who work with children and vulnerable adults.

Categorising legitimate free speech and dissent as “domestic extremism” intimidates and alienates people from taking part in protest activities, restricting their ability to exercise their rights to freedom of assembly and association. This cannot continue.

Already this year, the European court of human rights in Strasbourg has ruled that police acted unlawfully in compiling and retaining records about the political activities of campaigners John and Linda Catt on a “domestic extremism” database (Protester, 94, wins long battle to be deleted from police database, 25 January). It added that UK law in this area is too vague to provide adequate protection against the arbitrary use of police powers.

We collectively support the demands of the Network for Police Monitoring’s “Protest Is Not Extremism” campaign, which calls on the police to stop categorising campaigning and protest activities as domestic extremism. We also seek a clear separation of protest policing from counter-terrorism and better protection for campaigners against surveillance, including independent oversight of how police use it in relation to political protest.

Kevin Blowe Coordinator, Network for Police Monitoring (Netpol)

John and Linda Catt Campaigners who successfully challenged the police’s “domestic extremism” database

Shamik Dutta Bhatt Murphy, John and Linda Catt’s solicitor

Jenny Jones Green, House of Lords

Silkie Carlo Director, Big Brother Watch

Deborah Coles Executive director, Inquest

Mark Thomas Writer and performer

Dave Timms Friends of the Earth

Sheena Mooney Reclaim the Power

Kate Hudson Campaign for Nuclear Disarmament

Alexandra Phillips MEP Green, South East England

Joe Corré Talk Fracking

Dr Gail Bradbrook Co-founder of Extinction Rebellion

Claire James Campaign Against Climate Change

Millie Graham Wood Privacy International

Eveline Lubbers and Donal O’Driscoll Undercover Research Group

Estella Schmid Campaign Against Criminalising Communities

Anna Vickerstaff 350.org

Graham Thompson Co-founder of Plane Stupid

Asad Rehman Anti-racist campaigner

Melanie Gingell Peace in Kurdistan

Emily Apple Journalist and campaigner

Rebecca Lush Environmental campaigner

Professor Gargi Bhattacharyya University of East London

David Mead Professor of UK human rights law, University of East Anglia

Professor David Miller University of Bristol

Dr Tanzil Chowhdury Lecturer in public law, Queen Mary University of London

Dr Will Jackson Liverpool John Moores University

Dr Asim Qureshi CAGE

Dr Hilary Aked Researcher and campaigner

Professor Emeritus Nick Cowern Newcastle University

Dr Andrea Brock University of Sussex

Catherine Harrington Frack Off London

Claire Stephenson and Bob Dennett Frack Free Lancashire

Tina Rothery UK Nanas

Tom Wainwright Barrister, Garden Court Chambers and co-author of The Protest Handbook

Michael Hamilton Senior lecturer in public protest law, University of East Anglia, and secretary of the OSCE-ODIHR panel of experts on freedom of assembly

Damien Short Director, Human Rights Consortium, and reader in human rights, Institute of Commonwealth Studies

Andy Meinke Activist Court Aid Brigade

Carol Towner Protest Justice

Lydia Dagostino Solicitor, Kellys

Simon Pook Solicitor, Lizars

Mike Schwarz Solicitor, Bindmans

Rachel Harger Solicitor, Bindmans

Ian Brownhill Barrister

Owen Greenhall Barrister, Garden Court Chambers

Alex Gask Barrister, Doughty Street Chambers

Matt Foot Solicitor, Birnberg Peirce

Jules Carey Solicitor, Bindmans

Raj Chada Solicitor, Hodge Jones & Allen

Lochlinn Parker Solicitor, ITN

Patrick Ormerod Solicitor, Bindmans

Michael Oswald Solicitor, Bhatt Murphy

Simon Natas Solicitor, ITN

Steven Bird Solicitor, Birds

Ewa Jasiewicz Union organiser, activist and writer

Liam Geary Baulch Extinction Rebellion

Phil Ball Activist, Arctic 30

Richard Scholey Woodsetts Against Fracking

Steve Mason Frack Free United

Richard Roberts Reclaim the Power/one of the “Frack Free Four”

Rich Loizou Reclaim the Power/one of the “Frack Free Four”

Maureen Mills Halsall Against Fracking

Barbara Richardson Roseacre Awareness Group

Susan Gough Frack Free Kirby Misperton

Liz Cruse Pagans United Against Fracking

Andy Andrews Frack Free Somerset

Julie Daniels Lancashire Nanas

Lorraine Inglis Weald Action Group

Peter Scott Environmental campaigner

Jojo Mehta Frack Free Five Valleys

Merilyn Tarplee The Moss Alliance

Kathryn McWhirter No Fibs (No Fracking in Balcombe Society)

Benjamin Dean Environmental campaigner

Dr Jill Sutcliffe Keep Kirdford and Wisborough Green

Vivien Murchison Concerned Communities of Falkirk

Alan Flint and Diane Bell Frack Free Yeovil

Aedín McLoughlin Good Energies Alliance Ireland

Owen Adams Frack off Our Forest (of Dean)

Diane Wood South Somerset Green party

Tim Dawes Unite Community, Shropshire branch

Chris Cannon SAFE – Singleton Against Fracked Environment

David Penney Keep East Lancashire Frack Free

Anna Currado and Emily Anderson Keep Billingshurst Frack Free

John Clandillon-Baker and Rosie Rechter East Kent Against Fracking

Ian Roberts Residents Action on Fylde Fracking

Rikki Blue Journalist, RealMedia.Press

Mike Hill Expert adviser, technical working group on Hydrocarbon-BREF, Joint Research Centre of the EU commission

Richard Lawson and Sue Young-Pugh Frack Free North Somerset

Cllr Lisa Scott Mole Valley Green party

Chris Cole Drone Wars UK

Martyn Lowe Close Capenhurst Campaign

Janie Mac Campaigner

Maggie Hartley Retired university lecturer

Michael Vickery Frack Free Yeovil

Pat Smith Dorking Climate Emergency

Graham Stewart South Lanarkshire Against Unconventional Gas

Jay Ginn Croydon Green party

Kevin and Teresa Ogilvie-White Frack Free EQS (Exmoor-Quantock-Sedgemoor)

Adrian Palmer Frack Free York and Villages

Thomas Barlow Rebel Cities

Michelle Easton Kirby Misperton Protectors

Ken Gorman Peace campaigner

Leigh Coghill Anti-fracking campaigner

Will Cottrell Chair, Brighton Energy Coop

Cllr Linda Johnson East Riding of Yorkshire council

Russell Scott Investigative journalist

David Adam and Barbara Hickman Frack Free Ryedale

Kim Hunter Frack Free Scarborough

Rob Basto Frack Free Surrey

Ellie Wyatt Frack Free Sussex

Steve Bolter and Peter Anthony Bruce Green Liberal Democrats

Juliet McBride Nukewatch

Josephine Downs Frack Free Malton & Norton

Sheila Menon Social justice campaigner, one of the ‘Heathrow 13’

Sian Sullivan Professor of environment and culture, Bath Spa University

Mike Hannis Senior lecturer in environmental humanities, Bath Spa University, and editor, The Land magazine

Professor Andy Stirling University of Sussex

Amber Huff Institute of Development Studies

Professor David Ockwell Professor of geography, University of Sussex

Andrea Cornwall Researcher

Jan Selby Professor of international relations, University of Sussex

Liz Khan Women in Black London

Jane Talents Trident Ploughshares

Professor Ian Scoones Institute of Development Studies, University of Sussex

Jean Hesketh Frack Free Dudleston

Peter Underwood London representative on the Green party regional council

Dr Judith Verweijen Lecturer in international relations, University of Sussex

Simon Reed Director, Conscience: Taxes for Peace not War

Richard Dixon-Payne Sustainable Hackney

June Bhooshi Sheffield Against Fracking

Dr Rebecca Elmhirst Reader in human geography, University of Brighton

Frank Jackson Former co-chair, World Disarmament Campaign

Tim Devereux Vice-chair, Movement for the Abolition of War

Guy Martin Environmental campaigner

Helen Steel Police Spies Out of Lives and one of the “McLibel Two”

Alan and Jane Finney Mosborough Against Fracking

Ian Pocock London Campaign Against Arms Trade

Steve Ballard Secretary, London Hazards Centre

Polly Bluck Tower Hamlets Women for Peace

Dr Rob Byrne Lecturer, University of Sussex