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HMRC internal manual

Debt Management and Banking Manual

Pre-enforcement: interest in enforcement proceedings: calculating interest

IDMS work items

The Interest Calculator function on IDMS provides you with an automatic summary of the interest position for each IDMS work item and details of how the interest has been calculated. It also enters interest details automatically on forms and letters produced by the IDMS system.

The function can also be used where you have to raise an interest charge clerically. Before calculating interest, make sure that the interest packages for IDMS work items are completed.

When a request for a claim or judgment is submitted to the CCBC (County Court Bulk Centre) IDMS automatically calculates the accrued interest and includes it in the claim or judgment request.

For guidance on raising formal interest charges on the HoD system see DMBM610070.

Self Assessment debts

Use function View Statement to see details of interest accrued to ‘today’. Where you need to calculate an interest charge, IRIS function SAIN enables you to calculate interest to a ‘forward’ date for enforcement cases

In SA, an interest charge cannot be raised before payment is made. You should keep a note of the amount of the interest you have included in the enforcement proceedings on the enforcement papers.

SAFE Charges

Where interest is chargeable a figure equalling the amount of “interest accrued to date” will be displayed on SAFE charge account alongside the charge itself.

SAFE does not raise interest charges before payment of the parent duty is made. When the parent duty is paid, where appropriate SAFE will automatically calculate and raise late payment interest charges.

Function “Post Interest” will provide a full calculation of forward interest if required.

Other duties or charges

Some charges are not pursued through the IDMS system and all necessary actions, including the calculation of interest, are clerical. SAIN is a multi-purpose calculator that can be used to calculate interest, but you must enter all the details of amounts and dates clerically.

For example, you should use SAIN to calculate interest on

  • BROCS In Year PAYE items where proceedings are commenced after 19 April (see DMBM610040)
  • Stamp Duty Land Tax.