They were told to find a cheaper way of doing things ( and if I recall correctly, were seriously advised NOT to look at a national structure, as it would be too difficult to implement).
In spite of that they felt (and therefore recommended), that if they could make ‘X’ savings by regionalising, then they could ‘obviously’ make greater savings by nationalising! So we perhaps need to look a little closer to home. ‘We’ did this to ourselves.
Some forces already worked and funded jointly and also provided an ad hoc service to a force without their own ASU. It worked well.