Roles are used to achieve political ends.

Neither love nor the division of labor, neither the common attitude of two toward a third nor friendship, neither party affiliation nor superordination of subordination is likely by itself alone to produce or permanently sustain an actual group … the process which is given one name actually contains several distinguishable forms of relation.

In the end, those at the top of a company have certain duties to discharge and there are an endless number of ways in which those duties can be divided. The posts of chairman, deputy chairman, chief executive, and senior independent director can be held in different combinations by four, three, or even two people. The objectives remain the same: to provide clear leadership, to ensure that the board is effective and the business is well managed, and to represent the company to the outside world. The aim is to see that as many as possible of the qualities required for these different tasks are present among the members of the top team. How the tasks are allocated is less crucial than that there should be trust between the members of the team and no confusion about who does what.