Banks and financial analysts around the world have warned investors of volatility in jittery markets as the results from the U.K. referendum come in. Many analysts have predicted double-digit percentage moves for U.K. and EU equities in case of an exit, while a significant relief rally is anticipated in case of a remain vote.

"While GBP (sterling) may come under significant pressure, the euro may be more stable. Risk currencies (Swiss francs & the yen) would benefit, but policy responses could limit the degree of strength quickly. We think Euro-area core yields and UK yields would decline substantially (roughly 10-40 bps), and potentially even more so in the US," UBS Global Research said in a research note.

With so much uncertainty surrounding the results, investors have been advised by many analysts to be cautious when trading.

"Be very very careful. Stay invested, stay diversified," William Hobbs, Head of Investment Strategy U.K. and Europe at Barclays Wealth and Investment Management told CNBC on TV. "For the most part, remember that the U.K. economy for the most part is a very small contributor to the world's economy. It is even smaller contributor to world's capital market."

Meanwhile, financial advisers in the U.K have urged investors to not follow the 'herd' since markets tend to react as traders follow each other. Tony Catt, a London-based financial adviser says a lot depends on what the results are but the bigger risk is if the U.K. votes to exit.