Regulators around the world are looking at the way important financial benchmarks have been calculated. These are used to set the value of pension funds, investments and international contracts worth billions of pounds. Financial regulators in the UK, across Europe and in the US are investigating whether the benchmarks have been rigged to increase bank profits - and to short change their customers.

Banks are already receiving big fines over the LIBOR interest rate scandal but the focus is now shifting to the way prices in the foreign exchange, gold and interest rate swap markets have been set. Reporter Lesley Curwen assesses the evidence that banks have got together to manipulate the markets and asks what it means for the reputation of London as a global financial sector and public confidence in banking.

Producer: David Lewis.