Use form TC689 to get urgent authorisation to act on your client's behalf.
Use this form if you urgently need authorisation to act on your client’s behalf - and you have the paper form TC689 completed by your client.
Claiming and dealing with tax credits for someone else
How to deal with the Tax Credit Office for someone else, including how to get authorisation.
16 July 2013
HM Revenue & Customs
Tax credits: forms, notes, worksheets and checklists
Child Benefit forms
Don’t include personal or financial information like your National Insurance number or credit card details.