There is quite a lot of literature showing how to find the distribution of shear stress on a thin multi‐walled section under the action of an applied torque. In actual fact, however, before this torque can be assessed, it is necessary to know the position of the flexural axis of the section, the flexural axis being so positioned that when a shear is applied along it the section does not experience any torque. A method of finding the distribution of direct shear stress and hence the position of the flexural axis for a 2‐cell and then a 3‐cell section is explained.