In June 2026, Companies House confirmed a sweeping package of changes to how UK companies must file their annual accounts. The reforms, introduced under the Economic Crime and Corporate Transparency Act 2023 (ECCTA), will take effect from April 1st 2028. That gives accounting firms and their clients roughly 20 months to prepare. It sounds like plenty of time. It is not.
The changes affect every UK-registered company, regardless of size. If your firm files accounts on behalf of clients, the impact on your workflows, software, and client communications will be significant. Here is what you need to understand now.
From April 2028, all companies must file their annual accounts using commercial software. The existing Companies House web filing service and paper-based routes will be closed for accounts submissions. There are no exceptions.
Accounts will need to be produced in Inline eXtensible Business Reporting Language (iXBRL) format. This means every figure and piece of text in a set of accounts must be digitally tagged to a recognised taxonomy before submission. Companies that currently prepare accounts in Microsoft Word or Excel will need software that can apply iXBRL tags to those documents before filing.
It is worth noting that web filing for non-accounts submissions, such as confirmation statements and director updates, will remain available. But for accounts, the web route closes completely.
One of the most significant changes for small business clients is the requirement for small companies and micro-entities to file a profit and loss account with Companies House. Previously, these companies could file balance-sheet-only accounts, keeping their revenue and profitability figures off the public register.
Following strong representations from the profession, the government has included an important concession: smaller companies will be able to opt out of having their profit and loss account published on the public register. Companies House will still receive the information, but it will not necessarily be visible to the public. The precise mechanism for opting out has not yet been confirmed.
This is a conversation your firm needs to have with affected clients well before April 2028. Many will be surprised to learn that their financial performance will need to be shared with Companies House, even if it remains private from competitors.
The option to file abridged accounts is being removed entirely. Currently, small companies can choose to file a reduced version of their accounts that omits the profit and loss account and certain notes. From April 2028, this option will no longer exist.
For firms that routinely file abridged accounts on behalf of small company clients, this represents a direct change to your filing process. Clients who have relied on abridged filing to limit disclosure will need to understand what full filing means for them, and whether the opt-out mechanism for profit and loss publication will meet their concerns.
Every company claiming an audit exemption will be required to provide a strengthened eligibility statement that clearly identifies the specific exemption being relied upon and confirms the company's eligibility to use it. This is a tightening of existing requirements and is designed to reduce the number of companies incorrectly claiming exemptions.
Firms should review their standard accounts templates and engagement processes to ensure the new statement requirements are built in ahead of the April 2028 deadline.
Several further changes will be introduced alongside the headline reforms:
Companies House originally planned to introduce these changes in April 2027. Following concerns raised by businesses and their advisers, the implementation date was moved back to April 2028, giving companies what Companies House describes as one full accounting year plus nine months, or 21 months in total, to prepare.
But for accounting firms, the practical preparation window is shorter than that. You will need to:
Firms that leave this to the last quarter of 2027 will face a compressed rush at exactly the time when year-end compliance workloads are already heavy.
The April 2028 changes represent the third and final major package of reforms under ECCTA, following the introduction of enhanced Companies House powers and the identity verification requirements already in train. Taken together, they represent the most significant overhaul of UK company accounts filing in a generation.
For accounting firms, the shift to software-only iXBRL filing is not simply a compliance requirement. It is an opportunity to review your end-to-end accounts production process, consolidate your software stack, and ensure every client is on a filing route that will still work in 2028 and beyond.
TaxCalc will continue to publish guidance as further details, including the opt-out mechanism for small company profit and loss accounts, are confirmed by Companies House. In the meantime, the best thing your firm can do is start the planning conversation now.