Filing your CT600 when your accounts are already at Companies House

Many companies file their accounts at Companies House first — through Tax Optimiser, another agent, or on paper — and only then turn to the Company Tax Return. You can file just the CT600 in Tax Optimiser, but there is one thing to understand first: HMRC needs a full set of accounts with the return, and Tax Optimiser builds that set from the figures in your accounting period. So the period has to hold the same accounts you filed at Companies House.

What HMRC needs, and why it differs from Companies House

Most small companies file filleted accounts at Companies House: the balance sheet and notes, without the profit and loss account or the directors’ report. HMRC instead expects the full statutory accounts — the same accounts the directors approved, including the profit and loss account and, for a small company, the directors’ report (a micro-entity does not have to prepare one) — attached to the CT600 in iXBRL format, together with the tax computation.

Tax Optimiser produces both versions from the same trial balance, notes and directors, and always attaches the full version to the CT600. You can’t upload a copy of accounts prepared elsewhere, so the figures need to be entered in the period. See Full or filleted: what gets filed where for more on the two versions.

Create a new accounting period — don’t override the CT dates

The year you filed at Companies House is often missing from your list of periods. Sync from Companies House only creates the next period due, which is the year after the one you have already filed. It is tempting to open that period and use CT Dates → Override to point the return at the earlier year. Please don’t: it won’t produce the return you need.

The CT Dates override changes only the dates the CT600 covers. It does not change the accounts. The full accounts attached to the return, and the profit the tax computation starts from, still come from that period’s own dates and its own trial balance. So:

• the override has to fall within the accounting period, so dates from an earlier year are refused;
• where an override is accepted, HMRC receives a return for one set of dates with accounts headed for another — accounts that don’t match what you filed at Companies House;
• the period you borrowed still needs its own figures for its own year’s accounts and CT600.

Instead, give the filed accounts a period of their own. Go to Accounts and Corporation Tax, press Create, and enter the start and end dates of the accounts you filed. Leave the next year’s period as it is. See How to create an accounting period for each field on the form.

Set up the period to match the filed accounts

• Period dates. Use exactly the start and end dates of the accounts you filed. Leave CT Dates showing Same as accounting period unless the company was within the charge to Corporation Tax for only part of the period.
• Accounts Type. Choose the same standard used for the filed accounts — FRS 105 (micro-entity) or FRS 102 Section 1A (small company). Set this before entering figures: changing it later clears the trial balance and notes.
• Prior year. If the filed accounts showed prior-year figures, enter those too so the comparatives match.

Enter the figures

Enter the trial balance the filed accounts were prepared from, using whichever route suits you: Simple Entry, a trial balance import, a Xero or QuickBooks connection, or manual entry. Then complete the parts of the accounts that aren’t figures:

• the directors (and who signed the accounts) and the registered office;
• the notes the filed accounts carried, such as the average number of employees, guarantees and any advances to directors;
• the principal activity, which appears in the directors’ report.

Use the same approval date

Open the Corporation Tax computation and, on the General tab, set the Directors’ signage date to the date the directors approved the accounts — the date printed on the balance sheet you filed at Companies House. The CT600 can’t be sent without it.

If you are declaring the return on a later day, leave the signage date alone and enter that day in CT600 declaration date (optional) just below it. Box 980 then shows the declaration date while the accounts keep their approval date: see CT600 declaration date.

Mark Companies House as not required

On the period Overview, at the foot of the Companies House accounts steps in the Setup Process Checklist, click Mark as not required and confirm. This hides the Companies House submission and its checklist for the period, so nobody files the accounts a second time. Accounts stays available, because the accounts are still needed for the CT600. If you change your mind, click Mark as required.

Check the accounts match before you send

Download the accounts you filed from the Companies House register (the company’s Filing history) and compare them with the Review Document step of the Corporation Tax submission wizard, which shows exactly what HMRC will receive. Check:

• total assets, net current assets and net assets;
• share capital and reserves;
• the prior-year column, if there is one;
• the approval date and the director who signed;
• the accounts standard and the notes.

The profit and loss account and any directors’ report appear only in the HMRC version if you filed filleted accounts — that is expected. Check the profit for the year against the directors’ approved accounts and against the movement in reserves on the balance sheet.

Tax Optimiser doesn’t compare the two filings for you, so this check matters. If something doesn’t match, correct the figures in the period rather than filing accounts that differ from the approved set.

Submit the CT600

Review the computation, then open File CT600 with HMRC and work through the wizard as usual: confirm the client has approved the accounts, review the accounts and the computation, choose the director accepting the declaration, and send. See Submitting to HMRC and Companies House for each step.