A UK limited company answers to two different government systems: Companies House for the official register, and HM Revenue and Customs (HMRC) for tax. Sending a document to the wrong one does not stop any clock, and the penalty still lands.
In this blog, we explain what is the Government Gateway. We then cover Companies House and HMRC filings, 2026 deadlines and penalties, and when a Corporate Services Provider can help.
What Is the Government Gateway and How Does It Differ from Companies House Filings?
The Government Gateway is the sign-in system for HMRC's online tax services, while registry filings go through a separate Companies House online account.
The Government Gateway is an HMRC sign-in service, running since 2001, that issues one username and password for most online tax services. A company uses it to manage HMRC services; Company Tax Returns must normally be filed through commercial software, VAT returns through MTD-compatible software, and RTI reports through payroll software. It is free to create, and one person can hold several business roles under a single account.
Companies House works differently. Its online filing service relies on a company authentication code posted to the registered office, not on a Gateway login. Directors and people with significant control (PSC) must also verify their identity. This duty began on 18 November 2025 under the Economic Crime and Corporate Transparency Act. Verification can be completed through GOV.UK One Login or an Authorised Corporate Service Provider; existing directors provide their personal code with the next confirmation statement, while PSCs have role-specific 14-day deadlines.
The two systems do not merge. Companies House filings and HMRC submissions are generally separate, but Companies House tells HMRC when it approves a change of registered office address. Directors who assume one login covers both bodies are often the ones who miss deadlines.
1. The Government Gateway: HMRC's tax sign-in
The Gateway holds credentials for Corporation Tax, VAT, PAYE and Self Assessment. Company officers and appointed agents can both enrol, and each sees only the taxes linked to their role.
2. Companies House online filing: the registry route
Companies House filings use an authentication code issued to the registered office. Officer and PSC identity verification is a separate step through GOV.UK One Login under rules in force since November 2025.
3. GOV.UK One Login: the new identity layer
GOV.UK One Login is gradually replacing Gateway credentials across government services. Companies should watch for migration notices, so that an expired login never blocks a filing.
Which Companies House Filings Does Every Company Owe?
- The confirmation statement, at least once every 12 months
- Annual accounts, due even when the company is dormant
- Changes to officers, PSCs, share capital and the registered office
Every UK company starts with a set of formation documents. Form IN01, the memorandum of association and the articles of association go to Companies House together with the PSC details. The standard digital incorporation fee is £100, in force since February 2026, and the certificate with the company registration number is typically issued within 24 hours. Our United Kingdom company incorporation services handle this first stage end to end.
Before that, founders choose between the types of business entities to set up in the UK. The filing calendar depends on the form chosen. A private limited company carries the obligations described below; other structures differ.
After formation, a yearly rhythm applies. Every company, including dormant and non-trading ones, must file a confirmation statement (form CS01). The review period runs for 12 months, and the statement is due within 14 days of it ending. That 14-day window is the tightest deadline in the UK compliance calendar. The fee is £50 online or £110 on paper, per the Companies House fee schedule updated in July 2026.
Annual accounts go to Companies House as well. A private company normally files within 9 months of its accounting reference date; first accounts covering more than 12 months are due within 21 months of incorporation or 3 months after the accounting reference date, whichever is longer. Event-driven filings, such as a new director or a change of registered office, must be reported to Companies House within 14 days of the change.
Step 1: File the formation documents
Form IN01, the memorandum and the articles, plus PSC details, are lodged at incorporation. Identity verification for directors is now part of this process.
Step 2: Confirm the register each year
The confirmation statement confirms that Companies House holds correct data on officers, PSCs, share capital and SIC codes. It is owed even when nothing has changed.
Step 3: File annual accounts
Accounts are normally due 9 months after the accounting reference date; first accounts covering more than 12 months are due within 21 months of incorporation or 3 months after the accounting reference date, whichever is longer. Dormant companies must still file.
Step 4: Report changes as they happen
Officer appointments, resignations, PSC updates and address changes are generally filed within 14 days, while share allotments must be reported within one month. Statutory registers must stay accurate at all times.
Where Each UK Filing Goes in 2026
| Filing | Where it goes | Sign-in or key |
|---|---|---|
| Incorporation (IN01, articles) | Companies House | Online filing service |
| Confirmation statement (CS01) | Companies House | Company authentication code |
| Annual accounts | Companies House | Company authentication code |
| Officer, PSC and address changes | Companies House | Company authentication code |
| Corporation Tax registration and CT600 | HMRC | Government Gateway |
| VAT returns and PAYE submissions | HMRC | Government Gateway |
| Identity verification (ECCTA) | Companies House | GOV.UK One Login |
Which Filings Go Through HMRC's Government Gateway?
Corporation Tax registration is completed through HMRC online services; CT600 returns are filed using commercial software, VAT returns using MTD-compatible software, and RTI reports using payroll software.
According to HMRC, a company must register for Corporation Tax within 3 months of starting to trade. For companies with profits up to £1.5 million, payment is due 9 months and 1 day after the accounting period ends. Larger companies, or companies required to pay by instalments, can have different payment dates. The CT600 return follows within 12 months, filed online with accounts and computations attached.
Payment comes before the return. Companies that treat the 12-month filing date as the real deadline discover the payment date retroactively, with interest running from the due date.
VAT registration becomes compulsory once taxable turnover exceeds £90,000. Once registered, returns are submitted through the Gateway under Making Tax Digital rules, using compatible software. Employers use the same HMRC account for RTI payroll submissions every time staff are paid.
1. Corporation Tax registration
HMRC requires registration within 3 months of active trading. Late registration can delay the payment reference and create avoidable interest problems.
2. The CT600 Company Tax Return
The return is due 12 months after the accounting period ends and must be filed online. Accounts and tax computations are attached to the submission.
3. VAT and PAYE submissions
VAT returns follow Making Tax Digital rules through compatible software. PAYE real-time submissions run through the same Government Gateway account.
UK Filing Deadlines for 2026
| Obligation | Deadline | Fee or exposure |
|---|---|---|
| Confirmation statement (CS01) | 14 days after the 12-month review period ends | £50 online, £110 paper |
| First annual accounts | 21 months after incorporation | Late penalties from £150 |
| Annual accounts (private company) | 9 months after the accounting reference date | Late penalties from £150 |
| Corporation Tax payment | 9 months and 1 day after the accounting period | Interest from the due date |
| CT600 Company Tax Return | 12 months after the accounting period | £200 penalty from day 1 |
| Corporation Tax registration | Within 3 months of starting to trade | Interest risk if delayed |
When Are the 2026 Filing Deadlines and What Do Penalties Cost?
Accounts are due 9 months after the year end, the confirmation statement 14 days after the review period, and Corporation Tax 9 months and 1 day after the period ends.
The accounting reference date is set automatically at incorporation, falling on the last day of the incorporation month one year on. That single date drives every Companies House deadline that follows, which is why new directors should note it on day one.
Companies House rules state that late accounts penalties are automatic for private companies, starting at £150 and doubling when a company is late two years running. Since 1 April 2026, HMRC's late CT600 penalties start at £200 from the very first day, double their previous level, with further charges at 3, 6 and 12 months. The two regimes stack, so a company that misses both owes both.
One reform is worth tracking. Companies House's planned changes to accounts filing requirements were postponed to 1 April 2028. Nothing about deadlines or penalties changes before that date, despite older guides saying otherwise.
Late Filing Penalties in 2026
| How late | Accounts penalty (private company) | CT600 penalty |
|---|---|---|
| Up to 1 month | £150 | £200 from day 1 |
| 1 to 3 months | £375 | A further £200 at 3 months |
| 3 to 6 months | £750 | 10% of the unpaid tax at 6 months |
| More than 6 months | £1,500 | A further 10% at 12 months |
When Should a Company Get Professional Filing Support?
Professional support earns its fee when directors are overseas, the calendar is crowded, or a penalty has already landed.
In practice, we help clients in the UK and overseas keep both accounts healthy: registry filings on one side, HMRC obligations on the other. The workload is modest for a single active company, but it grows quickly with multiple entities, foreign directors and VAT in the mix.
A Corporate Services Provider can hold the entire filing calendar, prepare the documents, and act as agent through both HMRC and Companies House systems. That removes the most common failure point: a director remembering the tax deadline but forgetting the 14-day confirmation statement window, or the reverse.
For founders abroad, identity verification adds a step that is easier with guidance. Our comprehensive guideline covers starting a business in the United Kingdom from overseas, including how officers complete verification from another country.
Situations where professional support pays for itself:
- Non-resident directors managing postal delays and time zones
- Companies juggling registry, VAT and payroll deadlines on different dates
- Dormant companies that still owe accounts and a confirmation statement
- Groups needing one consolidated filing calendar across jurisdictions
- Companies recovering from a penalty who need help to reset the calendar
Conclusion
The split becomes clear when viewed correctly. The Government Gateway carries the HMRC side of a company's life. Companies House and its authentication code handle the registry side. The deadlines run on different clocks, and penalties for missing them can stack.
The key 2026 figures are:
- £50 for an online confirmation statement
- Annual accounts due 9 months after the year end
- A £200 CT600 late penalty from the first day
The 14-day confirmation statement window remains the easiest deadline to miss and the least forgiving.
3E Accounting United Kingdom is a Corporate Services Provider. It manages the full Companies House filing calendar, HMRC registrations and identity verification for companies of every size. The 3E Accounting International Network supports this work across more than 110 countries. To put the calendar in safe hands, contact us for a filing-health review.
Put Your UK Filing Calendar in Safe Hands
From the confirmation statement to the CT600, our team keeps every deadline on track and every filing with the right authority. Book a consultation and reset your compliance calendar.
Frequently Asked Questions
It is HMRC's sign-in system for online tax services, covering the CT600 Company Tax Return, VAT returns and PAYE submissions. It is entirely separate from Companies House filing.
No. Registry filings such as the confirmation statement and annual accounts are made through Companies House's own online service using the company authentication code, with officer identity verified through GOV.UK One Login.
The fee is £50 online or £110 on paper, payable once per 12-month payment period under the Companies House fee schedule updated in July 2026. Older guides quoting £34 or £40 are out of date.
Companies House penalties are automatic: £150 up to one month late, rising to £1,500 beyond six months. The penalty doubles if the company files late two years in a row.
According to HMRC, within 3 months of starting to trade. Payment is due 9 months and 1 day after the accounting period ends, and the CT600 return is due within 12 months.
Abigail Yu
Director
Abigail Yu oversees executive leadership at 3E Accounting Group, leading operations, IT solutions, public relations, and digital marketing to drive business success. She holds an honors degree in Communication and New Media from the National University of Singapore and is highly skilled in crisis management, financial communication, and corporate communications.
