EU-US trade talks to drift into 2016

"But it is clear that a completion of the negotiations, a conclusion of the agreement, that is something that will require more time than 2015," he added.

Trade officials were given a provisional deadline of December 2015 by EU leaders to agree a draft text, and are keen to avoid TTIP getting caught up in the race to replace Barack Obama in the White House.

The race for the US presidency will begin in earnest in autumn, when the Democratic and Republican parties begin their nomination process ahead of the presidential election in November 2016, and the election cycle will reduce the likelihood of a smooth ratification process through the US Congress.

However, Bercero played down concerns of an election-induced political deadlock, commenting that the Americans were “telling us very clearly that they can continue negotiating with us in 2016".

The most thorny issue for the two sides remains the status of investor protection mechanism known as ISDS, which allows firms to take governments to court if they discriminate against them or introduce new laws which threaten their investments. ISDS has been left out of the scope of talks since last spring amid widespread public concern about the regime.

But the status of genetically modified food became the latest bone of contention last week after the United States criticised EU plans that would allow countries to block genetically modified imports.

"It is hard to square this proposal with either EU long-standing internal obligations or their aspiration for a seamless internal market," Dan Mullaney, the US lead negotiator told reporters. "We are still studying the proposal implications but we hope that the EU will move forward in a way that respects our decades-old rules on trade," he added.

The disagreements and delays also risk seeing the Obama administration focusing its attention on ratifying a rival trade pact, known as the trans-pacific partnership (TPP), with Japan and ten other Pacific countries. After five years of negotiations, the TPP is close to conclusion and has begun its process through congressional committees.

Still, having concluded the ninth round of negotiations in New York last week, officials have pencilled in another round of talks in July, and insist that discussions will enter an "intense" phase after the summer.

In the two years since talks began, both sides have negotiating proposals ready on technical barriers to trade and regulatory cooperation, and have discussed "all three pillars of the negotiations: market access, regulatory cooperation and rules,” an EU official told reporters in Brussels last week.

“Both sides have dedicated a lot of time to get into the nitty gritty of the details,” the official said.