Maternity pay workings / tax?

Miles16v

My wife is due to go on mat leave shortly :j and just trying to work out what she'll get. Mat scheme gives her:

Week 1-6 90% normal weekly pay SMP
7-18 SMP + 1/2 normal pay
19-39 SMP

SMP is £128.73.

Is normal weekly pay the gross amount, and do you get tax'd / NI'd / Pension'd on it?

It seems a bit perverse if the govt gives you SMP with one hand and taxes you on it, but then it also seems perverse if you get 90% of your gross pay without any deductions, as that would actually be a take home pay rise?

Same goes for weeks 7-18 where SMP + 1/2 gross pay is actually more than normal weekly take home, so would be an increase in pay without deductions.

Do all employers offer to get your pay averaged out over the mat period, so you get the same each month?

Thanks.

Miles16v

Ok, I've done some googling and it turns out that it is based on gross pay, but it does count towards your taxable income.

Ultimately though she'll be earnings less so there will be a tax benefit.