This guide is maintained as a current resource for September 2026 and covers only the laws of England and Wales. Information is for general guidance, not legal advice. Consult a qualified solicitor for advice specific to your situation.
Comprehensive guide to Companies House authentication codes in the UK. Learn what they are, how they are issued and used for online company filings, security considerations, how to request replacements, and practical steps for directors and authorised agents to manage statutory compliance.
In the United Kingdom, every limited company registered with Companies House receives an authentication code. This code is a key part of the process for managing a company's statutory records and filing information online. It acts as a secure electronic identifier, ensuring that only authorised individuals can make changes to a company's details using Companies House online services, such as WebFiling. Understanding what authentication codes are, how they work, how to request and use them, and what risks are involved is essential for directors, company secretaries, solicitors, and business owners.
What Is a Companies House Authentication Code?
A Companies House authentication code is a unique alphanumeric code issued by Companies House to a limited company after incorporation. It functions as a form of electronic signature, granting the holder authority to file information about the company online using the Companies House WebFiling service or compatible commercial software.
The code is associated with the company, not individual directors, and is required each time an online filing is made. Without it, users cannot update statutory information or submit important documents online.
Why Authentication Codes Matter
Authentication codes play a central role in corporate compliance and governance:
- They secure online access to file statutory returns and updates at Companies House.
- They protect the company's public register from unauthorised filings.
- They are necessary for filing documents such as confirmation statements, annual accounts, and changes to the business or officer details.
Using an authentication code helps ensure that company filings are traceable and that only authorised filings reach the statutory register, which forms a public record of the company's legal and financial position.
How Authentication Codes Are Issued
After a company is formed - whether by online or paper registration - Companies House will generate an authentication code for that company. The code is usually sent by post to the company's registered office address. It can take up to 10 working days for the postal delivery to arrive.
If access to the registered office address is not available (for example, if the company is newly formed and not yet operational at that address), Companies House may send the code to a director's home address instead, provided the correct details are supplied. The code cannot be sent by email or disclosed over the telephone for security reasons.
If the company has already been registered and you have misplaced the authentication code, Companies House offers an option to request a new code through the WebFiling service, which will again be sent by post to the registered office or another recorded address.
Using Authentication Codes
Authentication codes are required whenever filing statutory information online. Typical online filings that require the code include:
- Confirmation statements, which provide an annual snapshot of a company's directors, shareholders, and registered office;
- Annual accounts, documenting financial performance and statutory reporting;
- Changes to company details, such as directors, registered office address, company name, or share capital;
- Certain filings made through commercial software linked to Companies House systems.
When using the WebFiling service, users will normally be prompted to enter the company's authentication code to confirm they have the authority to submit information on behalf of the company. This step acts as an important security control to prevent unauthorised amendments.
From 13 October 2025, Companies House has moved WebFiling access to the GOV.UK One Login platform, which may also require the authentication code as part of the sign‑on process to verify that the user is authorised to file for the company.
Practical Steps to Obtain and Manage Your Code
1. Wait for the Initial Code After Incorporation
Once your company is incorporated, Companies House will mail the initial authentication code to the registered office address. Allow adequate time for delivery, especially if postal delays occur.
2. Request a Replacement If Lost
If the code is lost or mislaid, log in to the WebFiling service and select the option to request an authentication code. Companies House will post a replacement to the registered office or an alternative address on record.
3. Keep the Code Secure
Treat the authentication code like a password. Do not share it widely. Directors or authorised agents should safeguard it and only provide it to trusted persons authorised to file on the company's behalf. Misuse or loss of the code could allow unauthorised filings.
4. Update Addresses if Necessary
If your registered office address changes, ensure you update this in the Companies House register promptly. A wrong or outdated address can delay receiving the code by post. If the code has not arrived, check the registered address on the public register and correct it if needed before requesting a replacement.
Security and Risks
Authentication codes help protect a company's statutory filings, but they also pose security risks if mishandled. Common concerns include:
- Unauthorised access: If the code is shared insecurely or falls into the wrong hands, someone could file inappropriate or damaging information for the company.
- Loss of access: Misplacing the code can lead to delays in meeting statutory deadlines, potentially resulting in penalties or non‑compliance issues.
- Changing agents: When switching accountants, solicitors or company administrators, make sure control over the authentication code is properly transferred to prevent lock‑outs that could disrupt filings.
Keeping control of the code and associated accounts is critical to maintaining compliance and avoiding disputes with third parties who may have previously used the code.
Common Questions
Can the authentication code be emailed?
No. Companies House will not email or disclose the authentication code by telephone for security reasons. It is sent by postal delivery only.
What if I never received the code?
If the initial code never arrives, check the registered office address on the Companies House public register. If the address is incorrect, correct it first and then request a new authentication code via WebFiling.
Do I need the code for every filing?
Yes. Any online filing made for the company through the WebFiling service generally requires the authentication code to confirm that the filer is authorised. Without it, the system will not allow the submission.
What happens when the code is compromised?
If the code is believed to be compromised, contact Companies House to request a replacement and take steps to secure access, including updating relevant account credentials and limiting distribution to authorised individuals.
Key Takeaways
A Companies House authentication code is a unique identifier issued post‑incorporation that allows a company to file statutory information online. It is essential for submitting confirmation statements, annual accounts and other updates via the WebFiling service or integrated software. The code is sent by post to the company's registered office or a director's address and must be safeguarded to prevent unauthorised use. If lost, a replacement can be requested through Companies House, though delays in delivery or incorrect registered addresses can slow progress. Maintaining control of the authentication code is an important part of corporate compliance and effective governance for limited companies in England and Wales.
