HMRC's CATO Service Has Closed: Where Your Old CT600 Returns Are Now

HMRC's Company Accounts and Tax Online (CATO) service — the free HMRC tool most small companies used to file their own CT600 — closed permanently on 31 March 2026. The filing history that used to sit inside it is no longer viewable online, and nothing in HMRC's current online services replaces it.

This guide explains what that means for you, where copies of your old returns actually are, and what to do if you need one.

I Signed In to HMRC and Cannot Find My Filed Returns

This is the first thing to know, because it saves a wasted search.

Your HMRC Business Tax Account does not hold a viewable or downloadable copy of a submitted CT600. There is no "View return", "Filed returns" or "Filing history" option for Corporation Tax, and there never was one outside CATO. What the Business Tax Account shows is your Corporation Tax account: the accounting periods HMRC holds, what has been charged, and what has been paid. It does not show the return document, its box figures, the computation or the accounts.

If you have signed in, found only a breakdown of tax and payments, and concluded the return is not there — you are right, and nothing is wrong with your account.

Where Your Old Returns Actually Are

Which route applies depends on how each return was filed.

Filed through CATO by you, and you downloaded copies before it closed

Those copies are the only self-service record. Check your own files, email attachments and cloud storage before anything else — most people saved a PDF at the time and have forgotten.

Filed by an accountant or tax agent

This is the quickest source by a wide margin. An accountant or agent must keep records of the returns they filed on your behalf and can normally send you a copy the same day. The obligation to retain those records still applies even if they have stopped acting for you or stopped practising. Ask for:

• The CT600 for each year you need, and the accompanying computation
• Or, if you only need one figure, the losses carried forward from the last return they filed (Box 780 for trading losses, Box 800 for property losses)

Filed through commercial software you still have access to

Your copy is stored in that software. Sign in and look for the submission or filing history for the company.

Filed through TinyTax

Every CT600, computation and set of accounts you have submitted through TinyTax is stored against your company and can be downloaded at any time from Filing History on your dashboard. Nothing you filed here was affected by CATO closing.

Ask HMRC in Writing

If none of the above produces a copy, HMRC can tell you what it holds for an accounting period — but not through a self-service screen. You have to ask.

Write to HMRC quoting your company UTR and the accounting period you need, and say what you are asking for. HMRC's Corporation Tax helpline on 0300 200 3410 will confirm the current postal address and what they are able to release. Expect this to take some weeks, so treat it as the fallback rather than the first step.

If You Only Need Last Year's Figures

Most people searching for an old CT600 actually need one of two things, and neither requires the return itself.

The prior year balance sheet (comparatives for this year's accounts)

Your filed accounts are on the public register, free, immediately:

1. Go to find-and-update.company-information.service.gov.uk and search for your company
2. Open the Filing history tab
3. Find the accounts for the year you need and download the PDF

That gives you the balance sheet as filed, including the comparative column. Note that accounts on the Companies House register do not contain your CT600 box figures or your tax computation.

Losses carried forward

If your company made losses in earlier years, you need the figure from the last CT600 filed:

• Trading losses: Box 780 on that CT600
• Property losses: Box 800 on that CT600

Enter this in TinyTax in the Losses brought forward from prior years field inside the Tax computation section (click Show ▾ next to Losses to reveal it). You only need the total from the most recent year filed — each CT600 already accumulates all prior losses.

Keeping Records From Now On

CATO's closure is a reminder that HMRC's online services are not a filing archive. Keep your own copies:

• Download the CT600, computation and accounts for every return at the time you file it
• Keep them for at least 6 years after the end of the accounting period — HMRC can enquire into a return that far back, longer if it suspects fraud
• Store a copy somewhere other than the computer you filed from

Returns filed through TinyTax remain downloadable from your dashboard, but a local copy costs nothing and does not depend on any service staying open.

Frequently Asked Questions

Can HMRC restore my CATO access so I can download my returns?

No. The service has been withdrawn, not suspended, and its filing history is not available through any current HMRC online service.

HMRC says it holds no return for one of my periods. Does that mean the CATO copy is lost?

Those are different questions. HMRC's records of whether a return was received are unaffected by CATO closing — that is what the written request above will confirm. If HMRC genuinely holds no return for a period, it was never successfully filed, and it needs filing now rather than retrieving.

Will HMRC send me copies if I ask?

HMRC can confirm the details it holds for an accounting period on written request. It may not reproduce the original document exactly as you submitted it, and it is slow. An accountant's copy or your own download is always the better source where one exists.

Can I get copies on behalf of a client?

If you are the company's authorised agent, yes — the written route above applies. Quote the company UTR and your agent reference.

Related guides

• How to Access Your Previous CT600 Submissions
• How Losses Brought Forward Work