Britain leaving the EU would be a “serious risk to growth”, the leaders of all the G7 countries have said in a joint statement.
David Cameron and other world leaders from France, Germany, Italy, Japan, the United States, and Canada are meeting in Ise-Shima, Japan, for a summit this week.
Brexit was ranked alongside “escalated geopolitical conflicts, terrorism and refugee flows” as one of the main reasons global growth could be “below potential”.
“UK exit from the EU would reverse the trend toward greater global trade, investment and the jobs they create and is a further serious risk to growth,” the agreed statement warned.
Britain will vote on whether to leave the EU on 23 June this year after a pledge by Mr Cameron to hold one.
The warning by the world leaders comes as the Prime Minister denies he secretly backs Brexit – after accusation by his former ‘guru’ Steve Hilton that he is privately inclined to do so.
“I am not a closet anything. I have pretty much had the same view about Europe ever since I got involved in active politics," Mr Cameron told reporters at the summit.
“I have always taken the same view, which is that we are better off in this organisation but we should be aiming to reform this organisation, we should be looking to enhance the special status that Britain.
“I have never been a closet Brexiteer. I am absolutely passionate about getting the right result, getting this reform in Europe and remaining part of it. It's in Britain's national interest.”
The G7 joins the International Monetary Fund, the Bank of England, the Treasury, the OECD and the Institute for Fiscal Studies in warning that Brexit would have a negative impact on growth.
The Brexit campaign has previously dismissed such concerns, warnings, and research as scaremongering.
A spokesperson for Vote Leave, the official campaign, in particular this week described the respected IFS think-tank as the “paid-up propaganda arms of Brussels”.
The Treasury today added to its previous analysis by warning that leaving the EU could reduce the value of the average pension pot by nearly £2000.
Former work and pensions secretary Iain Duncan Smith however described that calculation as “utterly outrageous” and a “cynical attempt” to distract from higher immigration figures.
