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HMRC letter codes · Corporation Tax (CT)

CT600CGroup and consortium relief

Last reviewed 14 October 2026 · How Tax Letters checks its facts

In short

GOV.UK says the CT600C is the form for claiming or surrendering relief under group or consortium, or unrelieved foreign tax provisions.

“Use this form if you’re claiming or surrendering relief under group or consortium, or unrelieved foreign tax provisions.”

GOV.UK: Corporation Tax: group and consortium relief (CT600C) · checked 14 October 2026

Information, not advice: this page reports what HMRC, GOV.UK and the bodies named publish about CT600C. Each fact has its source and the day it was checked beside it.

What it asks

GOV.UK's guidance on completing the CT600C says to complete the pages if you are claiming or surrendering any amounts under the group and (or) consortium relief provisions.

“You need to complete these supplementary pages if you’re claiming or surrendering any: … amounts under the group and (or) consortium relief provisions”

GOV.UK: Completing the CT600C page for group and consortium relief · checked 14 October 2026

How to send it or apply

GOV.UK's CT600C page says to check when you need to send an online Company Tax Return before you download the form and send it in the post.

“Before you download the form and send it in the post, check when you need to send an online Company Tax Return.”

GOV.UK: Corporation Tax: group and consortium relief (CT600C) · checked 14 October 2026

Free help and HMRC contacts

For questions about the CT600C, HMRC's Corporation Tax enquiries line (GOV.UK) is 0300 200 3410, open Monday to Friday, 8am to 6pm and closed on bank holidays. GOV.UK has a “Find out about call charges” link.

“Call HMRC for help with general Corporation Tax enquiries. … Telephone: 0300 200 3410 … Opening times: Monday to Friday: 8am to 6pm. Closed bank holidays … Find out about call charges”

GOV.UK: Corporation Tax: general enquiries · checked 14 October 2026

Free help first

These routes are described by GOV.UK, TaxAid and Citizens Advice themselves.

  • HMRC's extra supportHMRC offers extra support if your health condition or personal circumstances make it difficult to contact HMRC, for example a mental health condition, financial hardship or being treated in hospital.
  • Someone to deal with HMRC for youYou can authorise a friend, relative or voluntary organisation to talk to HMRC for you and help you fill in forms.
  • TaxAidTaxAid helps people with tax problems who cannot pay for advice. Tax Help for Older People merged with TaxAid in July 2025.
  • Citizens AdviceCitizens Advice gives confidential advice online, over the phone and in person, for free.