The International Monetary Fund has recently issued a note on the possible effects of Britain leaving the European Union. The final referendum is due to take place on 23rd June this year and its results must be respected by the politicians. The IMF says, that Brexit is now the biggest risk in the whole Europe and that the negotiations between the EU and Britain about it may take several years. According to the Fund, such a radical action will hit the real estate prices, stock markets and costs of mortgages and other credits. The uncertainty caused by the possibility of Brexit also has an impact on the investment in Great Britain, both on domestic and foreign. This country is also facing a downfall of the GDP growth. The Fund experts say, that there is a chance for a positive growth, but only if there is no Brexit. Bank of England may be forced to intervene were the real estate prices to remain high, and credit action will be expanding. All those factors combined send an unclear message to people dealing with forex trading. Markets will probably become chaotic after the decision to leave is made, since it means a new era for the European financial net. On the one hand, forex trading is concentrated in the City and one can assume, that such a giant will remain untouched. On the other hand, nothing is now 100% certain. Brexit would also mean lots of trouble for trading platforms, because some difficulties can appear, or even traders may be reluctant to make deals in the risky environment. New situation will also force traders to modify their forex ea. The robots will instantaneous become outdated. All the new behavior patterns will have to be remade by trading platforms and traders themselves. This will surely create large costs and no one knows, if the online forex trading will be as cheap as it is now.