The ideal arrangement is to agree child maintenance informally between you.
If you cannot agree, either of you can apply to the Child Maintenance Service (‘CMS’) for a formal assessment. The CMS will assess maintenance at a percentage of the payers gross income depending on how many children require support.
Allowances are made for overnight stays with the paying parent and other children who are dependent on the payer.
If maintenance cannot be agreed and an assessment is required, the CMS makes charges by way of deduction from maintenance collected.
The CMS has extensive powers to enforce child maintenance.