Roberto Azevêdo, the Director-General of the World Trade Organization, has warned that Britain may risk losing influence in trade negotiations if it were to quit the EU during a hearing this morning at the European Parliament's International Trade Committee.
In response to a question from Liberal Democrat MEP Catherine Bearder, who asked what impact leaving the EU would have on the UK's place within the WTO, Mr Azevêdo stated:
"I think that's a call that the UK will have to make for itself."
"But of course, the more that a country or a member is in a position to join with others in defending a particular idea or defending a particular agenda, the easier it is to push through its interests."
Ms Bearder, Liberal Democrat Trade Spokeswoman in the European Parliament, commented:
"UKIP and many Tories claim we can just pull out of Europe and trade using WTO rules, but now even the head of the WTO has turned round and said we are better off staying in."
"Being part of the world's largest trading bloc allows us to get a better deal for Britain and to open up new markets for our businesses overseas."
"Liberal Democrats are the party of In Europe because In is good for jobs, the economy and Britain's influence on the world stage."
A number of leading British business organisations have previously spoken out to emphasise the benefits that EU membership brings when it comes to global trade negotiations.
In a report in November 2013, the CBI stated that "the EU has helped open global markets to UK firms on terms that support its trading ambitions, through its leading role in global trade negotiations."