The deals could put the British taxpayers at the mercy of corporations that would be able to raid the public purse for compensation if they sue for lost profits.
The Trade Justice Movement, which includes Traidcraft, War on Want and Global Justice Now, says a government white paper on trade “gives no commitment to any role for Parliament in scrutinising such deals.”
Britain will regain authority to negotiate its own trade deals after leaving the European Union.
But deals proposed so far through the EU — including the Transatlantic Trade & Investment Partnership with the United States (TTIP), and the Comprehensive & Economic Trade Agreement with Canada (Ceta) — have included rules which force governments to offer public service contracts to multinational corporations.
They give corporations the power to sue governments which pass legislation that could affect their profits — such as the enforcement of minimum wages or health and safety regulations.
The campaigners say the white paper “hints at giving executive powers to ministers” to implement trade deals after Brexit.
Matt Grady of Traidcraft said: “There needs to be full scrutiny and a parliamentary vote on all trade deals.”
Mark Dearn of War on Want said: “To date, the government, in particular International Trade Secretary Liam Fox, has shown utter disdain for parliamentary scrutiny of trade deals.
“If the government is serious about respecting Parliament’s role in trade deals it must radically change its secretive approach.”
Jean Blaylock of the Trade Justice Movement said: “It is unacceptable to put in place such far-reaching trade deals without scrutiny, debate and votes by MPs.”