This is a hideously and legalistic difficult topic and relates to the arrangements it is possible to make in order to give power to an employee of one authority or agency to discharge the functions of another authority, and thus make two separate statutory functions join up. Staff swaps have been legitimate for years, but must be distinguished from the delegation of functions of one agency to another. It would probably make more sense in algebra than it does in prose but here goes:
A Health Act delegation
Reddington Health Authority delegates its s117 Mental Health Act function to Extonshire County Council
The LA mental health team is now able to discharge their own LA s117 functions and the s117 decision making functions of the HA. The HA employees may be TUPE’d over in any event.
This kind of delegation works either way – health to local authority, local authority to health. The acquiring LA as a body gains the power to discharge HA functions.
B Compare this with a Staff Swap:
Reddington HA seconds some of its staff to Extonshire under s113 of the LGA 1972. The staff count as the employees of the local authority from then on in. If they are seconded part time, they can exercise their old HA functions because they are still the employees of the HA, but also discharge LA functions.
The difference is that in the second example, the LA does not acquire any of the HA functions – they just move with the employee. If that employee leaves, the LA has no power to discharge the HA function that used to be discharged by that employee.
It is important to note that there is no equivalent provision under which Local authority staff can be seconded to health authorities and be made into HA employees. There is no power for the HA to arrange for the discharge of its functions by a person working for the LA, other than through Health Act flexibilities.