This is what the constitution says:
"210(3) No law may exclude or authorise the exclusion of a State officer from payment of tax by reason of—
(a) the office held by that State officer; or
(b) the nature of the work of the State officer."
"151(2) The remuneration, benefits and privileges of
the President and Deputy President shall not be varied to their disadvantage while in office."
"160(4) ...the remuneration and benefits payable to, or in respect of,
a judge shall not be varied to the disadvantage of that judge, and the retirement benefits of
a retired judge shall not be varied to the disadvantage of the retired judge during the lifetime of that retired judge."
"250(8) The remuneration and benefits payable to, or in respect of,
the members of a commission or the holder of an indepenedent (sic) office shall not be varied to the disadvantage of that person during their respective terms of office."
These clauses protect respective officers from the sort of action that MPs are facing. But the constitution is silent about MPs' salaries. It only establishes the Parliamentary Service Commission {whose members salaries are protected under 250(8).
In all honesty, that was unfair to the MPs - even though they have been unfair to us by not paying their full tax for two decades.
Their only way out is to get a good lawyer to convince a judge that the spirit of the constitution is "salaries should not be varied to the disadvantage of a person during their term of office." And that imposition of additional tax constitutes a variation.
But with Willy Mutunga now in office, I doubt whether they will be able to convince any judge...
Nothing is real unless it can be named; nothing has value unless it can be sold; money is worthless unless you spend it.