The UK's exit from the EU would have a global effect, which could hamper trade, investments and jobs, the G7 has warned. Following a meeting in Japan on 27 May, the leaders released a summit declaration referring to a Brexit as a "risk to global growth".

The comments, which come less than a month before the EU referendum vote, classified a Brexit alongside geopolitical conflicts, terrorism and refugee flows as having a potential shock of a "non-economic origin".

"A UK exit from the EU would reverse the trend towards greater global trade and investment, and the jobs they create, and is a further serious risk to growth," G7 leaders said in a 32-page declaration.

It was the only comment made regarding the possible split and German Chancellor Angela Merkel said the subject was not part of the summit's agenda and had not been discussed, but the leaders all agreed it would have negative effects.

"It was no subject here. But there was the signal that all who sat here want Britain to stay part of the EU," Merkel told reporters. "But the decision is up to the British voters."

The IMF also spoke in favour of a Remain vote, saying there were no economic positives to Britain leaving the EU. The Bank of England too pointed out that the economy would slow sharply and stated that there was a possibility of it causing a brief recession.

The Organisation for Economic Co-operation and Development (OECD) mentioned that a "Brexit tax" might be levied on British voters if it opts to leave the EU.

Jim Yong Kim and David Cameron
World Bank President Jim Yong Kim talks with British Prime Minister David Cameron of the last day of the G7 summitREUTERS/Carlos Barria