Green Party activists joined campaigners from the ‘38 Degrees’ organisation to hand out leaflets about the Transatlantic Trade and Investment Partnership (TTIP) in St Albans town centre on Saturday.
Jill Mills and Jack Easton were trying to raise awareness of the TTIP, an international trade deal that would allow big corporations to sue the British government if it passed laws which affected their business interests adversely - such as putting plain labels on cigarettes.
Campaigners believe the TTIP agreement is being negotiated in secret session by representatives of EU countries and could open the door to further privatisation of the NHS.
Jill Mills said: "Greens are completely opposed to this agreement and urge people to send a written protest to Vince Cable, who represents our government in these talks, and also to Anne Main, St Albans MP."
38 Degrees is one of the UK's biggest campaigning communities, with over 2.5 million members that get together and decide what issues to campaign.