The got a boost as expectations that the U.K. would remain in the EU mounted after the remain camp made advances ahead of Thursday's referendum.
Tthe trade-weighted pound soared 2.3 percent to 87.2, its best one-day performance since October 2008, according to Reuters.
Weekend polls showed the remain camp gained a narrow lead; a YouGov poll for The Sunday Times newspaper published at the weekend showed 44 percent supported remaining in the EU versus 43 percent who supported leaving, based on interviews conducted on Thursday and Friday. Two other polls also showed public opinion tilted towards the remain camp.
Given the fluid developments in the U.K., Vishnu Varathan, senior economist at Mizuho Bank wrote in a note Monday that there may be further volatility ahead in the forex market.
"If in-coming polls suggest 'Leave' resurgence, brace for another bout of 'risk off'," he added.