Europe's proposed free trade agreement with the US, known as Transatlantic Trade and Investment Partnership, would collapse if European leaders bowed to pressure to remove investment protection from any deal, the chairman of EU trade ministers has said.

Progress in the talks has slowed partly due to opposition from environmental groups as well as Germany, to the proposed Investor-State Dispute Settlement Clause (ISDS), which allows companies to take cross-border legal action against governments.

Critics have said that investment protection should be removed from the EU's negotiating mandate, but negotiators have repeatedly said that this would be tantamount to renegotiating the entire treaty.