I’ve completed a Self Assessment and don’t agree with the tax demand, what can I do?

Contact HMRC as soon as possible and ideally before the tax becomes due. The amount demanded may be wrong. In many cases, you may not agree with the amount of tax shown on your Statement of Account, or demanded by HMRC’s Debt Management and Banking section or debt collector. There could be a simple error - such as failure to credit a payment you have made - which can be sorted out by a phone call to the telephone number shown on your Statement of Account.