Investor confidence in Germany plummeted in July to its lowest level in nearly four years on concerns about the fallout for Europe's biggest economy from the British vote to quit the European Union, a leading survey showed on Tuesday.

The investor confidence index calculated by the ZEW economic institute plunged by a bigger-than-expected 26 points to minus 6.8 points in July, its lowest level since November 2012,  the think tank said in a statement.