"And our first priority must be achieving the most ambitious bilateral trade agreement in history – the EU-US free trade deal would benefit businesses on the whole continent, from business services in Spain to car manufacturers in the United Kingdom," the two leaders wrote in an opinion piece in the Expansion newspaper.
"So we stand up for this before our colleagues in Europe and the United States – let us make it possible this year," Cameron and Rajoy urged.
The Transatlantic Trade and Investment Partnership's stated goal is to ease the flow of goods and services across the Atlantic. The pact seeks to create the world's largest free trade zone, encompassing over 60 percent of global production.
Anti-TTIP activists have repeatedly pointed out that the TTIP deal has been negotiated in unusual secrecy, raising concerns that the agreement could benefit multinational corporations and corporate rights-holders at the expense of sovereign nations and consumers.