This part of GOV.UK is being rebuilt – find out what beta means

HMRC internal manual

Oils Technical Manual

Computer systems: duty calculation and reporting systems


The fundamental feature of any duty calculation and reporting system will be the use of master files to ensure the correct duty accounting. The master files will hold information concerning:

  • consignors & consignees;
  • product;
  • types of movement;
  • storage vessels;
  • excise duty rates and effective dates; and
  • accounting periods.

Transactions and the use of master files

It can be expected that the system will use master files when a transaction is created, filled and reported. The files can be expected to be used to:

  • identify the product as having an excise duty liability;
  • use consignee /consignor and product information to establish that the movement is allowable;
  • establish the dutiable quantity - density, temperature, Std./Nat. litres;
  • establish the duty liability; and
  • establish the entity responsible for duty payment

The validity of elements of transactions

The decisions made by systems should be established, documented and evaluated. The prime objective being that for any transaction the validity of the following elements is known:

  • date and time of movement;
  • the type of movement;
  • the duty status of the movement;
  • the dutiable quantity moved;
  • the rate of duty applied; and
  • the entity paying any excise duty

Master Files - other considerations

Remember that any calculations performed by duty calculation and reporting systems will only be as good as the quality of the information they use or capture, and hence the accuracy of any transactions performed by these systems are dependent on the quality of the data being held in the master files or captured from other sources.

It is therefore essential that the contents of the master files are correct and that any changes to these files can be identified and checked.

You should consider:

  • who has access to the master files
  • who has the ability to change the data contained in the master files
  • where the information contained in the master files or used in the transaction has come from, and
  • the accuracy of the information contained in the master files or transactions