There are options open to taxpayers who disagree with a tax decision issued by HMRC. It is important to note that not all decisions by HMRC can be appealed against.
HMRC makes it clear that a taxpayer who disagrees with a decision should send a letter within 30 days of the decision to state their disagreement. The taxpayer (or tax adviser) should include any additional relevant information whilst writing to appeal. A response to an appeal is usually made within 45 days but can take longer for complex issues.
Following this, if no agreement can be reached the taxpayer may ask for an independent review of the decision. If a taxpayer does not want a review or disagrees with the review, he can have the case heard by an independent tax tribunal. For direct tax cases, an appeal must be made to HMRC before referring the matter to the tribunal.
HMRC also describes in a relevant factsheet which taxes must be paid during reviews and appeals. Interest will continue to accrue on any postponed amount and unpaid tax that is found to be due when the appeal is settled, or the tribunal has made its decision.
There is a separate procedure to be followed by taxpayers that to make a complaint about HMRC for issues such as unreasonable delays, mistakes, and poor treatment by HMRC’s staff.
Source: Informanagement