On Thursday in parliament, MPs will get their first chance to debate post-Brexit trade deals, including with the United States. There is every sign that these deals will contain controversial investor-state dispute settlement (ISDS) mechanisms, after trade secretary Liam Fox reaffirmed the government’s support two weeks ago.

ISDS clauses in trade deals allow foreign investors to sue national governments for any measures that harm their profits. These cases take place in secretive private arbitration courts and can cost the taxpayer billions. Previous cases brought against governments using ISDS include a Swedish energy firm suing Germany for introducing policies to curb water pollution; US pharmaceutical giant Eli Lilly suing Canada for trying to keep medicines affordable; and French multinational Veolia suing Egypt for increasing its national minimum wage.

ISDS is a dangerous threat to human rights, health and the environment. It can make it difficult for governments to introduce policies on these issues, even when they have democratic support. This is particularly problematic for developing countries, which face a high proportion of cases, further depleting the resources they have available to implement the sustainable development goals. ISDS courts give international investors a legal system that neither ordinary people nor domestic businesses can access, with low levels of transparency, no appeals system and high costs.

Brexit means that the UK is likely to adopt an independent trade policy for the first time in over 40 years. As charities, trade unions and faith groups representing civil society, we are campaigning against ISDS in current and future trade and investment agreements. Liam Fox should take seriously the concerns of civil society and set out a trade policy that puts people and planet before corporate interests. Sign up at www.stopisds.org.uk

Dave Prentis General secretary, Unison

Craig Bennett CEO, Friends of the Earth England, Wales and Northern Ireland

Esther Stevenson CEO Traidcraft Exchange

Farah Nazeer Deputy director of advocacy, ActionAid UK

Nick Dearden Director, Global Justice Now

James Thornton CEO, ClientEarth

Martin Drewry Director, Health Poverty Action

Asad Rehman Executive director, War on Want

Ruth Bergan Senior advisor, Trade Justice Movement

Michael Buraimoh Director, Action for Southern Africa

Alistair Smith Director, Banana Link

Sarah Hirom Trustee, One World Week

Jim Killock Executive director, Open Rights Group

Liz Murray Coordinator, Trade Justice Scotland Coalition

Saoirse Fitzpatrick Advocacy manager, STOPAIDS

Marilyn Croser Director, CORE Coalition

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