Europe’s largest investment banks have spent the past three years trying to force the region’s main exchanges to cut their fees by ploughing money into alternative trading venues.

But just as the main exchanges - the London Stock Exchange, NYSE Euronext and Deutsche Börse - were facing up to four aggressive rivals - Chi-X, Turquoise, Nasdaq OMX Europe and Bats Trading - at the end of last year, the bottom fell out of the market and, with banks fighting for their lives, the need to shave a fraction of a basis point of trading costs lost its relevance.