Published by Jamie JemmesonThe euro tumbled versus the pound in foreign exchange trading yesterday (December 12th) to hit $1.3187 at 17:00 local time in New York.According to Bloomberg, this was a 1.5 per cent decline on the level seen the previous day and the multi-nation currency's worst performance since October 4th.Following European leaders' failure to produce an effective plan to resolve the ongoing deficit issues in the region last week, Moody's Investors Service stated it will considering changing the credit ratings of countries in the European Union (EU).Currency strategist at Wells Fargo & Co in New York Vassili Serebriakov said: "As markets continued to digest the announcement, they started taking a more negative view, which was reinforced by comments by Moody's."He added that an "ongoing erosion of optimism" has been seen following the meeting.Deputy prime minister Nick Clegg has recently told the BBC's Andrew Marr programme that the UK may become "isolated" from the rest of Europe if it cuts its ties with the EU.For more information on foreign exchange treasury services and risk management, visit our Corporate FX site