Check if a letter you’ve received from HMRC is genuine

If your letter is not listed here, you can:

Corporation Tax — declare your associated companies when claiming Marginal Relief

From 7 April 2026 up to and including 30 September 2026, HMRC may write to you.

HMRC may contact you by letter if our records show that you have not declared associated companies on a Company Tax Return when claiming Marginal Relief.

Associated companies reduce the profit limits for Marginal Relief and could mean more Corporation Tax is due.

If you believe your returns are correct, tell us why.

If you do not respond, we may take further action, including opening a compliance check.

Letter CA2490 — Home Responsibilities Protection eligibility

HMRC will send you a letter if we think you may have missing Home Responsibilities Protection (HRP).

We want to help you make sure you receive the right amount of State Pension, so we’re asking you to check if you were eligible for HRP between 1978 and 2010. You may have been eligible if you received Child Benefit for a child under 16.

The letter will tell you how you can check if you’re eligible to claim missing Home Responsibilities Protection and how to make a claim.

Letter CA4361 — National Insurance contributions

HMRC will contact you by letter if we think you may have paid too much in your National Insurance contributions.

We will ask you for information about your past employment.

We will tell you which tax years we need information for and we will include details of employers we have on our records.

The letter will ask you to reply by either:

We will then review the details you provide and confirm if you are due a refund.

HMRC may contact you by letter if you’re a young person with a matured Child Trust Fund.

The letter will ask you to contact your Child Trust Fund provider who will: