It's a subject that comes up frequently on mn. So if I may I'd like to make general points/suggestions that would massively improve things for resident parents and most importantly children :
1 change the calculations to more accurately reflect the actual costs of raising children! 16% of taxable income is pathetic! And absolutely remove all the loopholes that can reduce payments - calculate on gross pay not net!
2 if cm was taken at source via hmrc the cms would barely be needed! There is absolutely no good reason why this can't be done, it can then be calculated based on the most current income information held by hmrc and deducting at source would eliminate many of the issues with payments/collections there are currently. This would deal with the outright liars (where I live there are even certain employers who provide false payslips showing that their employee is on less pay than they actually get - and yes this has been reported but continues to happen) pay rises, overtime, bonuses, job hoppers etc
3 close the loopholes that too many self employed non resident parents use to falsely claim they are paupers on less than nmw and therefore lowering calculations.
Lifestyle evidence should be checked and taken into account where they're pleading poverty - while living in a 4 bed detached property, driving flash new cars, having multiple foreign holidays and enjoying use of the latest tech!
4 tricky with brexit, but negotiate with other countries to better pursue non resident parents who leave the uk.
5 USE the sanctions that are SUPPOSED to be available to deal with non or erratically paying parents! Hit these selfish people where it hurts! Make it that it's more convenient for them to pay and pay properly and regularly and REALLY INconvenient for them NOT to!
6 My dd is now working full time at 18 so fair enough that I don't get maintenance now for her BUT I should still be able to pursue the 16 YEARS of frequently missed payments, the arrears of which have never been properly followed up (and last I checked was £1000's) AND I think if a child is still in full time education OR returns to full time education (as my dd is debating doing) before age 25 (which is when they're considered "independent" for further/higher education funding purposes) then maintenance for that time should be paid too.
Children with non resident parents shouldn't face barriers to accessing further/higher education as a result.
7 agree with Xxwomen unite that resident parents shouldn't be having to pay because the non resident parent is taking the Mickey and not paying!
Happy touches on a suggestion that's often made on threads discussing this, that if the state paid cm and then recovered those payments from non resident parents children would then be receiving the payments guaranteed and the majority of us I'm sure would agree this would massively motivate the govt to recover that money front the paying parents!
Unfortunately I think it unlikely but I really see NO reason why it can't be deducted at source by the income tax dept. This would mean the vast majority of payments would be collected, would eliminate issues of dishonesty and delays in calculations catching up to pay rises etc decent non resident parents who don't have a problem paying would find it very easy and convenient.