The Bank of England is "looking into" what caused the pound to slump more than six percent against the dollar in less than ten minutes Friday, a spokesman told AFP.

"We are looking into what happened,"  he said after sterling suffered a "flash crash" in Asia trading hours -- hitting a new 31-year low point at $1.1841. The pound slumped also to a 6.5-year trough against the euro, at 94.15 pence.