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

HMRC internal manual

Tonnage Tax Manual

Offshore Activities: Capital allowances

Restriction where asset used for ‘offshore activities’ for part of accounting period

Where during an accounting period an asset used for ‘offshore activities’ is used for those activities on only some days, any writing down allowance for that period is restricted to the ‘relevant proportion’ of the full allowance.  See FA00/SCH22/PARA111 (1) & (2).

Qualifying expenditure for subsequent accounting periods

Any writing down allowance for a subsequent period is calculated as if the full allowance had been given in the earlier period.  SeeFA00/SCH22/PARA111 (3) & (4).

Calculation of ‘relevant proportion’

The relevant proportion of the full allowance to be given is calculated by:






  • OSD is the number of days on which the asset was used for ‘offshore activities’, and
  • APD is the total number of days in the accounting period.  See FA00/SCH22/PARA111 (5).

Where an asset is acquired part way through an accounting period HMRC interprets this by reference to the total number of days from the date of acquisition to the end of the accounting period.


FA00/SCH22/PARA111 (proportional reduction of allowances) TTM17631
Outline of capital allowance code for offshore activities TTM11300
Notional qualifying expenditure on existing assets TTM11310
Notional qualifying expenditure on new assets TTM11320
Example of offshore capital allowances TTM11340