The following are changes that you must tell the Tax Credit Office about within one month, or you may have to pay a penalty:

• when you stop being part of a couple;
• if you become part of a couple (including same-sex couples);
• if you leave the UK for more than eight weeks (or 12 weeks if the reason you had to leave is because you were ill or a member of your family was ill or has died) - your tax credit claim will end and you will need to make a new claim when you return;
• if you lose the right to stay in the UK;
• if you stop paying childcare costs, or your costs reduce by £10 or more for at least four weeks in a row - see Changes in childcare costs;
• if you stop working at least 16 or 30 hours a week; or
• if you stop being responsible for a child or young person you are claiming for, or the child or young person no longer qualifies for support, for example because a young person over 16 leaves full-time education of if the child dies.