Changes and issues affecting the Corporation Tax online service

Service issues

Account submissions using the FRC Taxonomy with the ‘Highest Paid Director’ tag

Accounts submitted to HMRC using the FRC Taxonomy that include the ‘Highest Paid Director’ tag are failing validation and are being rejected with the following error message:

‘3315 error message “Generic dimension member (bus:HighestPaidDirector) has no associated name or description item”.’

We are working with our IT supplier to resolve the problem.

If this issue means you cannot submit a return by the filing deadline you will not need to pay a penalty and do not need to take any action if you receive a penalty notice.

We apologise for any inconvenience.

Completing CT600N Residential Property Developer Tax (RPDT) and claiming RPDT group relief for carried forward losses

HMRC is aware of an online filing issue due to a restriction within the Corporation Tax online service.

You will only be affected if both the following apply:

• you are completing Section 3 Part 3 — claims to RPDT group relief for carried forward losses on supplementary page CT600N
• you do not have a simplified arrangement in place, so you must attach notices of consent

The service will be updated in April 2024 to fix this issue. If you need to file your return before this date, contact your Customer Compliance Manager.

Full expensing and 50% first-year allowances

As announced at Spring Budget 2023, companies incurring qualifying expenditure on plant or machinery on or after 1 April 2023, but before 1 April 2026 can claim:

• a 100% first-year allowance for main rate expenditure — this is known as full expensing
• a 50% first-year allowance for special rate expenditure

Find out more about full expensing.

The HMRC Corporation Tax online service will not be updated to support full expensing until April 2024. If you do not need to report this new relief, you can file online in the normal way before the Corporation Tax online service is updated.

If you need to submit either a full expensing or 50% first-year allowance claim, or both or report a balancing charge online before April 2024, you can do this using existing capital allowances boxes on the CT600.

For full expensing:

• boxes 725 and 750 should be used for claim amounts
• boxes 730 and 755 should be used to report balancing charges
• box 760 should be used for qualifying expenditure

You should do this until the online service has been updated and new boxes are available.

For the 50% first-year allowance:

• boxes 693 and 743 should be used for claim amounts
• boxes 694 and 744 should be used to report balancing charges
• box 773 should be used for qualifying expenditure

New boxes will not be added for the 50% first-year allowance and the CT600 guide will be amended soon. These boxes should continue to be used once the online service has been updated.

It will not be possible to claim full expensing or the 50% first-year allowance using the HMRC free filing service (Company Accounts and Tax Online (CATO)) — this service will not be updated to allow these claims.