The Swiss franc fell to its weakest level in 20 months as traders took advantage of the improved sentiment in Europe to dump what has been one of the most popular havens for investors in the euro zone crisis.

The move sent the franc to its lowest level since the Swiss National Bank intervened in September 2011 in an effort to protect its exporters from heavy inflows into Switzerland by overseas investors.

The central bank has vowed to buy as many euro as it takes to prevent the franc from moving below SFr1.20 against the single currency. The euro rose close to SFr1.25 yesterday. – Copyright The Financial Times Limited 2013