Its salary sacrifice…therefore reducing my gross pay, therefore paying less tax and NI………
Do you pay NI on pension contributions salary sacrifice?
The amount you sacrifice on your salary isn't subject to income tax or NI contributions. This saves you a bit extra, since standard pension tax relief only repays income tax and doesn't include NI.
Its one of the more misunderstood part of how salaries are treated. Google it.
If you do salary sacrifice, simple calculation of your latest payslip will tell you if it is gross or minus salary sacrifice.
I suspect it was designed from day 1 to prevent employers using "structuring" to reduce their share. Lower salary but higher allowances etc. So it is gross and takes away any shennigans.
Edit: NI does not include include salary sacrifice. Got t wrong earlier.