Senior officers say police need clarity about who is in charge of the new unified force, which officially starts in spring.

The Association of Scottish Police Superintendents (ASPS) called for an "outbreak of common sense" to resolve uncertainty over who will control key functions in the single force, ahead of the first meeting of the Scottish Police Authority (SPA) board next week.

The comments come amid ambiguity about the full functions of the new chief constable and the role of the civilian SPA, particularly over who will be in charge of some behind-the-scenes functions within the new Police Service of Scotland (PSoS).

ASPS believes Chief Constable Stephen House should be responsible for the direction and control of all resources and that the SPA should hold him to account. In addition, it insists the "critical functions" of finance and human resources must also come under his control.

Any attempt to have services split between the SPA and the new force would be "cumbersome, costly and once again produce the duplication police reform is trying to remove from current structures", senior officers said.

Earlier this week, the First Minister said the ambiguity is expected to be "ironed out in good time".

Alex Salmond said the power struggle between House and Vic Emery, chairman of the SPA, could be described as "creative tensions".