Tax credits claimants are reminded by HMRC to report changes in their circumstances - or they may receive more money than they are entitled to. They would have to pay this back and might face a financial penalty.

From April this year, any income increase for a household of more than £5,000 for the tax year will reduce a claimant's tax credits award for the 2013-14 tax year. This amount has fallen from the previous figure of £10,000, after a Budget announcement in 2010.

Claimants need to let HMRC know of any changes in their circumstances that they haven't already reported during the year. The changes could be about their working hours, childcare costs, living arrangements or income. They need to report the changes immediately and ensure the details they provide are correct.

HMRC's director general of Benefits and Credits, Nick Lodge, said: 'Many people forget or fail to tell us about important changes - such as having a partner move in or an increase in income - which will affect the amount of money they receive. This could mean that they don't get all the money they are entitled to. Or they could receive money that they have to pay back.

'We therefore urge them to report changes promptly, and make sure all details are accurate.'

Further details are available from HMRC at http://www.hmrc.gov.uk/taxcredits/index.htm