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HMRC letter codes · Corporation Tax (CT)

CT220Corporation Tax assessment

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

In short

A CT220 assessment shows the company's Corporation Tax position for the accounting period, usually based on the information in its Corporation Tax Return or on later amendments, and a letter E in front of a figure means an estimate (HMRC's CT220 notes).

“The assessment shows your company’s Corporation Tax position for the accounting period (AP). This is usually based on the information contained in your company’s Corporation Tax Return or on later amendments. We use estimated figures if you’ve not sent us enough information to make an accurate assessment. In this case there is a letter E in front of the figure.”

GOV.UK: Corporation Tax: assessments (CT220 Notes) · checked 14 October 2026

Information, not advice: this page reports what HMRC, GOV.UK and the bodies named publish about CT220. Each fact has its source and the day it was checked beside it.

What it is

HMRC's internal manual forms index lists the CT220 as a notice of assessment to a company showing its Corporation Tax liability for a CT Pay and File accounting period.

“Notice of assessment to a company showing its CT liability for a CT Pay and File AP.”

HMRC COTAX Manual: COM150, Forms index · checked 14 October 2026

What it asks

HMRC's CT220 notes say that if you think the assessment is correct and there is no tax to pay, all you need do is keep the assessment in case you need to refer to it in future, and that if there is tax to pay HMRC attaches a payment slip to the assessment showing how much.

“If you think the assessment is correct … If there’s no tax to pay, all you need do is keep the assessment in case you need to refer to it in future. If there is tax to pay we attach a payslip to the assessment showing how much.”

GOV.UK: Corporation Tax: assessments (CT220 Notes) · checked 14 October 2026

Time limits and rules

HMRC's CT220 notes say that if you do not agree with the amount of the assessment, you or the company's adviser may appeal by writing to the officer whose address is shown on the notice, within 30 days from the date on which the assessment was issued, and that even if you appeal you must pay the tax unless you also apply to postpone payment.

“If you don’t agree with the amount of the assessment, you or your company’s adviser may appeal against it by writing to the officer whose address is shown on the notice. … The appeal must be made within 30 days from the date on which the assessment was issued. … Even if you appeal you must pay the tax unless you also apply to postpone payment.”

GOV.UK: Corporation Tax: assessments (CT220 Notes) · checked 14 October 2026

Free help and HMRC contacts

For more information, HMRC's CT220 notes say to contact your HMRC office, stating the reference and assessment number shown at the top of the CT220 assessment.

“If you need more information, please contact your HMRC office stating the reference and assessment number shown at the top of the assessment.”

GOV.UK: Corporation Tax: assessments (CT220 Notes) · checked 14 October 2026

For questions about the CT220, 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.