Assumption: "Child maintenance carries on until my child is 18."

Court Reality

The rule is different from that. Through the Child Maintenance Service, maintenance covers a child under 16, or under 20 if they are still in approved education or training. Payments end when they leave that education or training, or turn 20, whichever happens first. Approved education includes courses such as A levels and most vocational qualifications up to level 3; full-time study at degree level is not approved education for this purpose. Child maintenance is linked to Child Benefit, so changes to a child's education are reported to the Child Benefit office, not the Child Maintenance Service. That catches people out in both directions: a parent expecting the payments to run to 18 can find they end sooner, and a parent paying can find them running on well past 18 because a young person is still in approved education. Private agreements and court orders can set different end dates. You can check the rule yourself on GOV.UK rather than take our word for it: https://www.gov.uk/child-maintenance-service/when-child-maintenance-stops