Instinet has reduced staff in its London office by 5% and several senior managers have left since it restructured its business in June. The institutional broker confirmed last week that about 5% of its London office had left, but any more departures would be "fine tuning".

However, a source at a recruitment consultant in London said the figure could reach more than 10%. The London office has 179 full-time employees as well as part-time contractors. Instinet Group employs 813.