What changed for directors

GOV.UK says the service to file company accounts and Company Tax Returns together closed on 31 March 2026. From 1 April 2026, companies should use commercial software to file annual accounts and Company Tax Returns with HMRC.

That matters for directors who previously used the free joint service. Filing a CT600 is still possible, but the route has changed. You need software that can prepare the Company Tax Return package and help you review what is being sent to HMRC.

What a director is actually filing

A Company Tax Return is more than the main CT600 form. HMRC guidance describes the return as the CT600, any supplementary pages, company accounts, computations, and relevant information. For online filing, accounts and computations usually need to be in Inline XBRL format.

That means director self-filing should start with the company records, not with the submit button. The software needs to help you connect accounts, tax adjustments, computations, supplementary pages, attachments, review, and Government Gateway submission.

When self-filing is a good fit

Director-led CT600 filing can work well for straightforward UK limited companies where the accounting records are tidy, the director understands the business activity, and there are no unresolved specialist tax issues.

It is usually a better fit when:

the company has one clear accounting period;
accounts and bookkeeping records are complete;
the director can explain the main income, expenses, assets, and liabilities;
tax adjustments are limited and understandable;
there are no complex claims, groups, overseas issues, or specialist reliefs;
the director is willing to review the return before filing.

When to get accountant help

Software can structure the filing workflow, but it does not replace professional judgment where the facts are difficult. A director should slow down or get advice before filing if the return includes judgement-heavy areas.

overdrawn directors' loan accounts or loans to shareholders;
R&D claims, creative industry claims, or other payable credits;
group companies, group relief, or transfers of losses;
large capital allowance claims or asset disposals;
unclear accounts, missing bank records, or unreconciled balances;
late, amended, rejected, or multiple-period returns;
anything where the director is unsure whether a supplementary page applies.

The director's pre-filing checklist

Before choosing software, gather the information a reviewer would need. Even if you are the reviewer, the file should show why the return is reasonable.

company name, Companies House number, UTR, and accounting period;
accounts for the period and supporting bookkeeping records;
profit and loss, balance sheet, fixed assets, and loan balances;
tax adjustments from accounting profit to taxable profit;
capital allowance additions, disposals, and pools;
losses brought forward, used, surrendered, or carried forward;
director loan movements and repayment dates;
details of reliefs, credits, or specialist activities;
Government Gateway access or agent authorisation.

Director loan accounts are the common trap

Many owner-managed companies look simple until the director's loan account is reviewed. If a close company has made a loan to a participator, or an associate of a participator, CT600A and section 455 tax may need to be considered.

The practical point is timing. A loan balance at the year end, repayments after the year end, releases, write-offs, and re-borrowing can all affect the return. Do not treat the director loan balance as just another balance-sheet line.

What good CT600 software should show a director

A director-friendly product should not hide the tax logic. It should make the return understandable enough that the director can approve it with confidence.

the CT600 accounting period and filing status;
how accounting profit becomes taxable profit;
which claims, reliefs, and losses are included;
whether any supplementary pages are included and why;
which accounts and computation attachments will be filed;
validation warnings before submission;
the final HMRC response and evidence of what was submitted.

How Robocount helps director-led filing

Robocount is built for UK Corporation Tax and CT600 filing rather than generic bookkeeping. Directors can work through the return in a browser, review the computation and supplementary-page position, and keep the filing package visible before submission.

CT600 preparation and review for company directors.
Plain-English return workflow around accounts, computations, and supported supplementary pages.
Director loan and owner-managed-company review points surfaced before filing.
Government Gateway filing workflow for supported returns.
API and AI-assisted workflow options for directors who want structured help without losing final approval.

FAQ

Can a director file a CT600 without an accountant?

Yes, if the director uses suitable software and is comfortable taking responsibility for the return. It is sensible to get professional help if the company has complex claims, unclear accounts, group issues, director loans, or specialist tax positions.

Do I still file accounts with Companies House?

Yes. Companies still need to meet Companies House accounts obligations and HMRC Company Tax Return obligations. The closed joint service changed the filing route, not the underlying duties.

Is the CT600 the same as the company accounts?

No. The CT600 is the Company Tax Return form. The return package can also include accounts, computations, supplementary pages, and other information. Accounts profit and Corporation Tax profit are not always the same.

What if my return is rejected?

Check the HMRC response, fix the validation or attachment issue, and keep evidence of the failed and corrected submission. Do not leave rejected-return handling until the deadline.

Useful official references

This guide is general product and filing workflow information, not tax advice. Check current GOV.UK guidance and the company's facts before filing.

CT600 software for directors: how to self-file without treating Corporation Tax like a form.