Working for HMRC tax work?

Assalamu alaykum. Perhaps @Mufti_Billal @Mufti_Faraz_Adam can shed some light on this issue.

Is it permissible to work for civil service where one calculates on tax liabilities but does have any involvement with interest. The salaries of civil servants are paid through tax ofcourse .

Thanks

Wasalam

May Allah bless you.
Calculating the tax liabilities is permissible.
However, if you are also involved in calculating the interest due, then this will not be acceptable.

And Allah knows best!