Dormant Return File for £5

HMRC's free filing service has closed. Here are your options.

By Max Szolcek, founder of Dormant Return. Last updated 21 August 2026

On 31 March 2026, HMRC and Companies House permanently closed the free "File your accounts and Company Tax Return" online service (often called CATO). Since 1 April 2026, a Company Tax Return can only be filed to HMRC using commercial software. For dormant companies, whose returns are almost entirely zeroes, this turned a free ten-minute job into a paid one.

What exactly closed

The joint service let a company file its annual accounts to Companies House and its Company Tax Return (CT600) to HMRC in one place, for free. It closed because, in the government's words, it was outdated and did not align with modern digital standards or with changes to UK company law under the Economic Crime and Corporate Transparency Act 2023.

Returns previously filed through the service are no longer accessible or amendable through it, which is why HMRC advised companies to download at least their last three years of filings before the closure.

What the rules are now

The closure changed how you file, not whether you file. If HMRC has sent your company a notice to deliver a return, the deadline and the late filing penalties apply exactly as before. Whether your dormant company needs to file at all is covered in do dormant companies need to file a CT600?

Your options as a dormant company

1. Check whether you need to file at all

If HMRC has not issued a notice to deliver a return and the company has genuinely never traded in the period, you may be able to tell HMRC the company is dormant and avoid the return entirely. This is the cheapest option: free. It only works if HMRC agrees and stops expecting a return; a notice already issued still has to be answered with a filed return.

2. Use commercial software built for full accounts and tax

General Corporation Tax packages aimed at accountants and trading companies typically cost roughly £80 to £100 or more per year. They will file a dormant return, but you are paying for computations, reliefs and features a dormant company will never touch.

3. Use a service built for dormant returns

A dormant return needs a CT600 of zeroes and a set of dormant accounts tagged in iXBRL (explained in dormant company iXBRL accounts explained). Because the shape of the return is always the same, it can be automated end to end, which is what Dormant Return does: a single £5 filing, no subscription, filed under your own Government Gateway sign-in. The walkthrough is in how to file a dormant company CT600 online.

4. Pay an accountant

Perfectly sensible if the company's affairs are not actually simple, or you want advice on whether the company is dormant in the first place. Expect a fee well above software prices for a one-off dormant return.

The five-minute route: Dormant Return prepares your CT600 and iXBRL dormant accounts and files them straight to HMRC. £5 one-off, refunded automatically if HMRC rejects the return.

Start your return

Related guides

Sources