Julien Hammerson, the dynamic head of European equities at Instinet, the institutional brokerage, has left the company following a dispute over its direction.

He left two weeks ago after a row over management strategy following a restructuring of the business last year, which saw the agency broking business split from the US-based electronic communications network. In December, Natan Tiefenbrun, former senior vice-president of the global portfolio trading division, was appointed president of the London-based agency broking business.