Companies House Filing Changes — April 2026

What Changed on 1 April 2026

Several major changes took effect on 1 April 2026, all stemming from the Economic Crime and Corporate Transparency Act 2023 (ECCTA) and Companies House's ongoing digital transformation programme. The headline changes are:

• The Companies House WebFiling service for annual accounts has permanently closed
• All annual accounts must now be submitted in iXBRL format via approved commercial software
• HMRC's free online CT600 filing service has also ended
• The joint filing system that allowed small companies to submit accounts and corporation tax returns together through HMRC has been withdrawn

These changes affect every UK limited company, from single-director micro-entities to large PLCs. If you are a company director, you need to understand what has changed and act accordingly.

WebFiling for Accounts Has Ended

The Companies House WebFiling service allowed directors to upload annual accounts directly through the Companies House website. This service closed for annual accounts on 31 March 2026.

According to Companies House, the old WebFiling service did not meet modern data standards. The system could not validate accounts data with the granularity now required under ECCTA reforms, and it did not support the structured iXBRL format that Companies House needs for its enhanced data analysis capabilities.

If you previously filed your own accounts through WebFiling without an accountant, you will now need to use commercial filing software or appoint a professional to file on your behalf.

What About Other WebFiling Services?

The closure only applies to annual accounts filing. You can still use Companies House online services to:

• File your confirmation statement (formerly annual return)
• Report changes to director or secretary details
• Update your registered office address
• File changes to people with significant control (PSCs)

iXBRL Is Now Mandatory

iXBRL stands for Inline eXtensible Business Reporting Language. It is a format that embeds structured, machine-readable tags within a human-readable document. This allows Companies House (and HMRC) to automatically extract and validate every figure in your accounts.

From 1 April 2026, all annual accounts submitted to Companies House must be in iXBRL format. This applies regardless of company size, including:

• Micro-entity accounts (FRS 105)
• Small company accounts (FRS 102 Section 1A)
• Dormant company accounts
• Medium and large company accounts

You do not need to understand iXBRL technically. The commercial software generates the tagged file for you. But you do need software capable of producing it.

HMRC Free CT600 Filing Has Also Ended

In a parallel change, HMRC's free online service for filing Corporation Tax returns (CT600) also closed on 31 March 2026. Companies that previously filed their CT600 directly through the HMRC website must now use commercial software.

This aligns with the government's broader "file once, use many times" strategy. HMRC wants accounts and tax returns to be consistent and cross-referenced automatically. Any mismatch between what you file with Companies House and what you file with HMRC could trigger an enquiry.

For most small companies, this means you will need software that handles both Companies House accounts and HMRC CT600 returns, or you will need to use two separate tools.

Software Options for Filing Accounts

You now need commercial software to file accounts. The good news is that several affordable options exist, including some that are free or very low cost for basic filings:

When choosing software, check that it can produce iXBRL-tagged accounts in the correct taxonomy for your company size. If you file as a micro-entity (FRS 105), confirm the software supports that specific format.

You will also need your Companies House authentication code — the six-character code used for WebFiling. If you have lost it, you can request a reminder to be posted to your registered office through the Companies House website.

Identity Verification for Directors and PSCs

Under the ECCTA reforms, all company directors and persons with significant control (PSCs) must now complete identity verification with Companies House. This requirement has been phasing in since 18 November 2025.

The Timeline

• 18 November 2025: Identity verification became available. New directors appointed from this date must provide a unique identifier (UI) code. Companies cannot file a confirmation statement without providing UI codes for all directors appointed within the relevant period.
• November 2026: The transition period ends. By this date, all existing directors and PSCs must have completed identity verification. Those who have not verified will be unable to make filings.

How Identity Verification Works

Directors and PSCs can verify their identity in two ways:

• Directly with Companies House — through the online identity verification service
• Through an Authorised Corporate Service Provider (ACSP) — such as a solicitor, accountant, or company formation agent who is registered with a supervisory body

Once verified, you receive a unique identifier (UI) code. This code must be provided on your company's confirmation statement.

Why This Matters

The identity verification requirement is designed to prevent fraudulent company setups and ensure that only genuine individuals control UK companies. According to Companies House, it is part of wider reforms under ECCTA to "protect against the misuse of UK corporate structures."

If you are a director and have not yet verified your identity, you should do so well before the November 2026 deadline. Leaving it late risks being unable to file your confirmation statement.

Other ECCTA Changes Already in Effect

Several other ECCTA changes have already taken effect that directors should be aware of:

Registered Email Address (Since March 2024)

Every company must have a registered email address on file with Companies House. This was introduced on 5 March 2024. The email is not published on the public register but is used by Companies House for official communications about the company. Directors have a duty to keep it up to date.

Lawful Purpose Statement (Since March 2025)

Since 5 March 2025, every company must confirm on its annual confirmation statement that all intended future activities will be lawful. Confirmation statements without this declaration ticked will not be accepted by Companies House.

Increased Companies House Fees

Companies House fees have increased as part of the reform programme. The incorporation fee has risen and the confirmation statement fee is now higher than in previous years. These increases fund the enhanced verification and enforcement capabilities that the ECCTA requires.

Appropriate Address Requirement

Companies House now has greater powers to query and reject registered office addresses that are not "appropriate." A PO Box alone is no longer acceptable. The registered office must be a physical address where documents can be delivered and acknowledged.

What Has Not Changed

Not everything is different. The following remain the same:

• Filing deadlines — Private companies still have 9 months after their accounting reference date to file accounts. PLCs still have 6 months.
• Late filing penalties — The penalty regime is unchanged (ranging from £150 to £1,500 for private companies, doubled if late two years running).
• Confirmation statements — These can still be filed through the Companies House website. The WebFiling closure only affects annual accounts.
• Company size thresholds — The criteria for micro-entity, small, medium, and large companies remain the same.
• Director notification deadlines — Changes to directors, addresses, and PSCs must still be reported within 14 days.

For a full overview of ongoing filing obligations, see our Companies House Filing Requirements guide.

Penalties for Getting It Wrong

The shift to mandatory software filing and identity verification means there is less room for error. Companies House's enhanced data validation will automatically flag inconsistencies between accounts data, and cross-referencing with HMRC means discrepancies between tax returns and filed accounts are more likely to be detected.

Directors who fail to comply face:

• Late filing penalties — £150 to £1,500 (private companies), doubled for repeat offenders
• Strike-off — Companies House can remove the company from the register if filings are persistently overdue
• Personal prosecution — Directors can face personal fines or criminal records for failure to file
• Disqualification — Directors may be barred from acting as a director of any company

With the new digital infrastructure, Companies House has stated that enforcement activity is expected to increase.

What Directors Should Do Now

If you are a director of a UK limited company, here is your checklist:

Frequently Asked Questions