An agency for getting an absent, separated, or divorced parent to pay their share of upkeep for a child. Often much reviled.

In Britain the CSA is part of the Department for Work and Pensions, introduced in 1993. There are separate but related CSA schemes for England and Wales, for Scotland, and for Northern Ireland. (The rumour that the England and Wales branch is paying maintenance to the others is frivolous.) The following relates to their system.

One parent is defined as the Parent With Care and the other as the Non Resident Parent. The latter might be anyone from one who has shared custody of the child but has fewer nights with it; to an anonymous cad who eats, roots, and leaves. The CSA has strong powers to force disclosure of income and addresses, to send in the bailiffs, and to compel employers to operate Deduction from Earnings orders. Unlike other Attachments of Earnings such as Council Tax, they don't need to go through a court to get this order.

Until 2003 the amounts payable were decided by the CSA after consideration of the incomes of the two parents and the present partner of the Parent With Care. The liable parent has a protected amount of earnings, such that CSA deductions cannot cause their net pay in any given period to fall below this protected amount. If the CSA payment due is not therefore payable in full from the excess over these earnings, the outstanding part of the amount is carried forward to the next period.

The protected amount can also be carried forward. It is meant to be an average net earnings needed by the liable parent. If in any period their actual net pay falls below the protected amount, the shortfall is carried over and added into next period's protected amount, so that the average is not disrupted.

An employer can deduct £1 more to cover administration of an order. This is allowed to eat into the protected salary.

Effective from 3 March 2003 the amounts payable are based on fixed rates and on the number of children. Non-resident parents on a low income, up to £100 a week, pay £5 a week. Between £200 and £2000 a week the amount of net earnings payable is 15% for one child, 20% for two, and 25% for three or more. Allowance at the same rates is made for any children in their new family. This system only applies to new cases, but the intention is to gradually transfer existing child support arrangements across to it.

Learn all about it at www.csa.gov.uk