European Union trade ministers agreed Thursday to launch negotiations on a mega-sized free trade deal with Japan while pledging to safeguard Europe's struggling carmakers.

"We now have a clear mandate, confirmed by all the member states," said Europe's Trade Commissioner Karel De Gucht after ministers gave the European Commission a green light to open talks on a free trade deal, or FTA, which could take several years to negotiate.

Britain's Trade Minister Stephen Green immediately welcomed "the first big step towards liberalizing trade between two of the world's largest economies," which together account for more than a third of the globe's output.

But he cautioned that the EU was "starting out on a journey that will be long, tedious and painstaking."

It "could be three years, maybe more" before a deal, and "we could easily be talking about 10 years or more before we get full impact," he said.

But carmakers quickly slammed what the European Automobile Manufacturers' Association dubbed "a one-way street' for Japanese automakers.

France, whose flagship auto giant Peugeot Citroen (IW 1000/47) is in trouble, said it agreed to the negotiations after winning assurances of a balanced deal.