The triple (and double) differential cross sections for electron impact ionisation of helium and molecular hydrogen are investigated to a much higher accuracy than obtained before. In a coplanar symmetric geometry ( theta =45 degrees ) both electrons emerging from the ionisation event-with equal velocities- are detected in coincidence. Over the impact energy range from 200 to 2800 eV the authors present absolute triple (double) differential cross sections containing an experimental error smaller than 20(10)%. A detailed comparison is made with results from various theoretical approaches.