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HMRC internal manual

Tonnage Tax Manual

Introduction to tonnage Tax: The tonnage tax return (CT600F)

Where a tonnage tax company makes a return of its Corporation Tax liability for an accounting period, in addition to the CT600, it must complete a supplementary return for tonnage tax, form CT600F

Features of the tonnage tax return

Features of the CT600 and CT600F relating to tonnage tax include:

  • An ‘X’ to be inserted in the appropriate supplementary return box (summary of return information) on the front page of the CT600, to indicate that a CT600F is attached.

  • The tonnage tax profit, see TTM01300 as computed in box F10 on the CT600F, to be inserted in box 145 on page 6 in the ‘detailed calculation’.

  • Any deduction for training allowance by a tonnage tax company that is engaged in offshore activities (TTM11400) should be carried from box 8 on the CT600F to box 61 on page 8 of the CT600.

  • Part 1 of the CT600F consists of a ‘check-box’ series of statements. Where there is a representative company dealing with the affairs of a tonnage tax group, each company should answer ‘not applicable’ on statement F5 on the 75% limit (TTM05001). Instead, the representative company should answer the question on behalf of the group at F6.

  • Part 2 has only two boxes on the offshore training allowance. Box F8 is carried to box 61 of the CT600 (see above), but the second box at F9 is the only record of a carry forward of excess training allowance.

  • Part 3 is the detailed return of tonnage tax profit computed for each ship.

  • Technical specialists should encourage the taxpayer and adviser to be accurate in completing the designation of interest column, because:

    • national statistics will be based on this,

    • information about leased ships is needed to enable liaison with Large Business (Financial), and

    • intra-group leasing will affect any checks on the 75% limit (TTM05000).

  • The total at F10 should have been carried to box 145 on the CT600.

  • Part 4 is an optional section relating to national statistics.

  • Where Part 4 has not been completed, officers should insert estimates of relevant shipping profits derived from an examination of the commercial accounts.

  • Detailed notes on completing the CT600F are given on page 4 of the form.


Action on receipt of CT600F TTM01410