Most divorced/seperated parents would naturally want to financially contribute to their children's wellbeing, however when the Non-resident parent (NRP) is asked to contribute up to 25% of their salary (new system post 2003) to the ex-partner for the 'welfare of the children'.
Due to most relationship breakups there are usually lotss of anger and bitterness by both parties that does not help the children, the biggest one of all is probably maintenance payments for the children; especially after the Parent With Care (PWC) usually receives up to 80% of all assest at point of divorce/seperation, because it's in the 'best interest of the children'.
I strongly believe this is one of the biggest problems of NRP's (NOT just fathers) of not paying. People resent the fact that the money they pay in child maintenance is actually not being spent on the children, therefore at least if a reasonable percentage; say 25%, of the payment is put in a trust fund, the NRP knows that one day (18 yrs old) the children would benefit from past payments, for University fees, etc.
The government can do what they want with the money, as long as the children get (at a minimum) of whas been paid in to it.