If your net taxable income last year was £50,000 or more you will shortly receive a letter from the Tax Office about child benefit. You can safely bin this missive if your children are no longer eligible for child benefit, but where you or your partner/spouse claim child benefit you need to pay attention.
This is because from 7 January 2013 the higher earner in the family (where that person has £50,000 or more of income) will be landed with a tax charge to clawback the child benefit claimed in respect of the children. The tax charge will equal 1% of the child benefit received by the family for every £100 of income over £50,000, so 100% of the child benefit will be clawed-back when the higher earner has net taxable income of £60,000 per year.
The tax charge only applies to child benefit paid from 7 January 2013 onwards, and will be calculated on your net taxable income for the current tax year: 2012/13. Net taxable income is income after deduction of losses, pension contributions and gift aid payments but before personal allowances. So there is some scope for reducing your net income below £50,000 by paying pension contributions, gift aid donations, or by taking a smaller dividend from your own company in the current tax year. But those strategies, and other ways to manage your income, need to continue until the children are no longer eligible for child benefit.
You will be given the option of declining to receive child benefit to avoid the tax charge, and this will be explained in the Taxman's letter. However, this is not the same as not making a claim for child benefit. It is important to make a claim for child benefit (even if you decline to receive it) as the claim can help entitlements to the state pension for a non-working parent, and ensures the child receives a NI number at age 15.