Every local government authority within the United Kingdom is required by statute to designate one of its officers to carry out the function of "Head of Paid Service", being the individual that has overall corporate management and operational responsibility or the way in which the organisation delivers its services.
To put it another way; somebody is supposed to be in charge. The title "Head of Paid Service" does not of course sound all that important, so people being what they are, very few heads of paid service are actually known by that name; more often than not the title Chief Executive is preferred.
It shall be the duty of every relevant authority to designate one of their officers as the head of their paid service
Section 4 (1) (a) of the Local Government and Housing Act 1989