The survey also showed that the vigorous trading in the pound since Britain's surprise decision last June to leave the European Union drove an 8 percent rise in trading of the currency against the dollar, to an average of $281 billion a day.

Overall volumes were depressed by a continuing fall off in spot currency trading, the report's data showed.

http://www.bankofengland.co.uk/markets/Documents/forex/fxjsc/2017/fxturnresults170124.pdf

(Reporting by Patrick Graham; editing by Marc Jones)