How to make a tax claim outside a tax return

If you have been asked to file a Self Assessment return, a claim that can be made in that return, or in an amendment to it, must be made there. A standalone claim is used where no return is required, where the law says the claim cannot go in a return, or where the return can no longer be amended but the claim’s own time limit is still open. It must follow Schedule 1A to the Taxes Management Act 1970 and, unless another rule applies, be made within four years of the end of the tax year.

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When must a claim go in the tax return?

Section 42(2) of the Taxes Management Act 1970 (TMA 1970) says that where you have been sent a notice to file a return under section 8, a claim must not be made otherwise than in the return if it could, at that time or later, be made in it. Section 42(5) treats an amendment to the return as part of the return. So the default for anyone in Self Assessment is to make the claim on the return or by amending it.

HMRC’s Self Assessment Claims Manual at SACM3030 adds a practical point: if HMRC receives a claim after the return has been filed but within the 12 month amendment window, it treats it as an amendment to the return. Amending the return itself is covered in our guide to amending a Self Assessment tax return.

Which claims can be made outside a return?

SACM3030 gives the main situations in which a claim cannot be made in a return and so is made on its own:

the person is outside Self Assessment and has neither been sent a notice to file nor filed voluntarily;
HMRC has agreed to withdraw the notice to file for that year;
the claim can be made before the end of the tax year or before a notice to file is issued;
the return amendment window has closed but the claim’s own time limit has not.

Some claims are taken outside the return by statute. Overpayment relief under Schedule 1AB may not be made in a return (paragraph 3(4)); see our page on overpayment relief. Claims to carry back a loss or payment to an earlier year fall under Schedule 1B, and paragraph 2(2) switches off section 42(2) for them. Claims dealt with through a PAYE code are excluded from section 42(2) by section 42(3). Someone who only needs a refund of tax taken from savings and is not in Self Assessment would normally use form R40.

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What form does a standalone claim have to take?

Paragraph 2 of Schedule 1A sets the minimum requirements:

the claim is made to an officer of HMRC;
a claim for repayment needs documentary proof that the tax was paid, by deduction or otherwise;
it must be in the form HMRC determines, which must include a declaration that the particulars are correctly stated to the best of the claimant’s information and belief;
the form may require a statement of the tax to be repaid or discharged, information reasonably needed to check the claim, and supporting accounts and documents;
a claimant who is, or claims to be, non resident or non domiciled can be required to support the claim by affidavit.

Section 42(1A) also requires a claim for a relief, allowance or repayment to be quantified when it is made. SACM3025 explains that this means giving HMRC enough information to give effect to the claim without further checking. SACM3015 notes that section 42 does not itself demand writing, but the legislation for a particular relief often does, and some claims can be made by telephone under Statement of Practice SP1/10.

What happens if the claim is defective?

SACM10010 treats an unsatisfactory claim as no claim at all. Examples include a claim not made on a prescribed form, a claim expressed as a formula rather than a figure, and a claim made outside a return when it should have been in one. For a loss carry back, HMRC expects the claim to state the source of the loss, its amount, the year it arose, the amount carried back and the year it goes to.

Because there is no valid claim, HMRC cannot open a statutory enquiry. If the deficiency comes to light near the deadline, the manual tells officers to allow a reasonable extension, usually 14 days, but that extension does not move the statutory time limit. Relief given after the limit is discretionary.

What time limits apply?

Section 43(1) TMA 1970 sets the general rule: no claim for income tax or capital gains tax relief may be made more than four years after the end of the tax year to which it relates, unless another provision sets a longer or shorter period. Many reliefs have their own limit. Trade loss relief against general income under section 64 of the Income Tax Act 2007, for example, must be claimed by the first anniversary of the normal Self Assessment filing date for the loss making year.

Section 43(2) gives extra time for a claim that could only be allowed because HMRC made an assessment after the end of the year: it can be made before the end of the tax year following the one in which the assessment was made. See our page on consequential claims after a late assessment and the wider table in time limits for tax claims.

A late claim has no effect unless HMRC agrees to accept it (SACM10035). SACM10045 states there is no right of appeal against a refusal to accept a late claim. The remedy is judicial review.

Can you change a standalone claim after sending it?

Under paragraph 3 of Schedule 1A, you can amend the claim by notice within 12 months of the day it was made, and HMRC can correct obvious errors within nine months. Neither can happen while an enquiry into the claim is open. After the 12 months, section 42(9) allows a supplementary claim to correct an error, as long as the time for making the original claim has not run out.

How does HMRC process and check it?

Paragraph 4 requires HMRC to give effect to the claim by discharge or repayment as soon as practicable. If HMRC opens an enquiry, that duty is suspended until the enquiry ends, although the officer may give effect to the claim provisionally.

The enquiry window in paragraph 5(2) is the latest of the quarter day after the first anniversary of the claim and, for a claim relating to a tax year, the first anniversary of the 31 January after that year. The quarter days are 31 January, 30 April, 31 July and 31 October. Paragraph 2A requires records supporting the claim to be kept until the enquiry window closes or any enquiry ends, with a penalty of up to £3,000 for failing to do so. What happens during that enquiry is explained in HMRC enquiries into claims outside a return.

How might a loss carry back claim look?

Illustration only. Nadia’s sole trade makes a loss of £18,000 in the 2025 to 2026 tax year. She was profitable in 2024 to 2025 and wants a repayment before filing her 2025 to 2026 return. She writes to HMRC stating the trade, the loss of £18,000, that it arose in 2025 to 2026, that she claims relief under section 64 against general income of 2024 to 2025, and the tax repayment she calculates. She signs a declaration and keeps the working papers.

Under Schedule 1B paragraph 2, the claim relates to the later year, 2025 to 2026, but is measured by the tax saving in 2024 to 2025, and effect is given in 2025 to 2026 by repayment or set off. Her 2024 to 2025 return is not reopened. Her deadline under section 64(5) is 31 January 2028.

What mistakes cause standalone claims to fail?

Writing to HMRC separately when the return is still open for amendment, so the claim is not validly made.
Sending a letter that describes a relief without stating the amount, the year and the statutory basis.
Missing a relief’s own deadline by assuming the four year rule applies.
Expecting an appeal right when HMRC refuses a late claim.
Not keeping the records that support the claim until the enquiry window has closed.

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Reviewed by Christine Anderson, Broker, Solar Protect. Last reviewed 24 October 2026. Part of Accountapedia, the Solar Protect guide to UK tax and accounting. This page is general information, not personalised advice.