I Lost My Companies House Authentication Code: What Should I Do?

If you have lost your Companies House authentication code, you can request a new copy of the code. You do not need to form a new company, and losing the code does not mean that your company record has been lost. The Companies House authentication code is a 6-character alphanumeric code used to authorise online filings for a company. Companies House describes it as the equivalent of a company officer's signature for online filing.

The code is different from your Companies House personal code, which is issued to an individual after identity verification. Confusing these two codes is increasingly common as Companies House introduces mandatory identity verification and GOV.UK One Login into its services.

If you have forgotten, misplaced or never received your company authentication code, the solution is generally straightforward: request the code through Companies House and have it sent by post to the company's registered office. In certain circumstances, Companies House can send it to an active officer's home address instead.

What Is a Companies House Authentication Code?

A Companies House authentication code is a 6-character combination of letters and numbers assigned to a company. It is used to prove that you are authorised to file information for that company online. You may need it when using Companies House services to:

• File annual accounts
• File a confirmation statement
• Change company information
• Appoint or resign directors
• Change a registered office
• Update certain company details
• File other information electronically
• Use commercial software to submit Companies House filings

Companies House says the same authentication code is used for the company when filing online through WebFiling, the Find and update company information service and compatible commercial software.

Authentication code vs personal code

These are two different credentials:

The personal code is associated with identity verification and is not a replacement for the company's authentication code. Companies House currently describes the personal code as an 11-character code issued to an individual after identity verification. This distinction is particularly important for directors who have recently completed identity verification.

I Lost My Authentication Code. What Should I Do?

If you have lost the code, you can request it again through Companies House. The current Companies House guidance says you should sign in to WebFiling and follow the process for requesting an authentication code. The code is sent by post to the company's registered office and can take up to 10 working days to arrive. The basic process is:

1. Sign in to Companies House WebFiling.
2. Choose the option to request an authentication code.
3. Enter your company number and the required details.
4. Confirm the company's registered office information.
5. Companies House sends the code by post.
6. Use the new code when completing your online filing.

If the company already has an authentication code, Companies House will generally send a reminder rather than create an entirely separate code.

How Long Does It Take to Get a Replacement Code?

Companies House currently says that an authentication code sent to the registered office can take up to 10 working days to arrive. That is important if your company's accounts or confirmation statement deadline is approaching.

Do not leave requesting the code until the day your filing is due. Companies House specifically advises companies not to wait until their accounts are due before requesting an authentication code because delivery can take longer than usual during busy periods.

A practical example

Suppose your company's annual accounts are due in two weeks and you discover that your accountant no longer has the authentication code. Waiting until the final few days creates an unnecessary risk. Request the code immediately, check that the registered office can receive the letter and allow enough time for postal delivery.

Where Will Companies House Send the New Code?

The normal destination is the company's registered office address. This is one reason it is important to keep your registered office details accurate and make sure you have a reliable way of receiving correspondence there. For founders using a registered office service, the provider may receive the letter on your behalf and then forward or scan it according to its service arrangements.

If you are an overseas founder, this can be particularly important. Your personal residence overseas is not normally where the company authentication code is sent simply because you are the director. Companies House uses the company's registered office for the normal authentication-code delivery process.

What If I Cannot Access My Registered Office?

There is a specific Companies House process for requesting the authentication code at an active officer's home address. This can be useful if, for example:

• You have lost access to your registered office.
• Your registered office service has ended.
• You cannot retrieve post from the registered office.
• You are concerned that the correspondence cannot be accessed.

Companies House says the home-address service requires the company number and a Companies House sign-in. The code is still sent by post, and delivery takes around 10 working days. The service cannot currently be used if the company:

• Filed a document online within the previous 30 days
• Is not based in the UK
• Is not a limited company or LLP
• Has been dissolved

You also need to be confident that Companies House holds the officer's most recent home address.

Can Companies House Email Me the Authentication Code?

No. Companies House does not send company authentication codes by email. It also does not provide the authentication code over the telephone. This is an important security feature.

If someone contacts you claiming to be from Companies House and asks you to provide your authentication code by email, telephone or through an online form, treat the request with caution. Companies House says it will never ask you for your authentication code over the phone or by email.

What If I Never Received My Original Authentication Code?

The process is similar. If you have recently incorporated a company and never received the authentication code, you can request it through Companies House. The code is posted to the company's registered office. Companies House's guidance for online filing states that a new code can take up to 10 working days to arrive. Before requesting it, check:

• The company is correctly registered.
• The registered office address is correct.
• Your mail-handling provider has not received the letter.
• You are using the correct Companies House account.
• You have not already requested a reminder.

If the address recorded at Companies House is wrong, deal with that issue rather than assuming the authentication code will somehow reach you.

What If My Registered Office Address Has Changed?

This can create a circular problem. You may need your authentication code to change certain company details online, while the old registered office may be where Companies House sends the code. Companies House provides a process for changing a registered office address, and its guidance confirms that the company authentication code is normally required for an online change.

If you cannot access the registered office, the home-address authentication-code service may be available, subject to its eligibility conditions. If that route is not available, you may need to use the appropriate Companies House support or alternative filing procedure.

The key point is do not assume that changing the registered office and obtaining the authentication code are unrelated tasks. The authentication code is part of the security mechanism protecting changes to company information.

Can My Accountant Request or Use the Code?

Your accountant or another authorised person can file information on behalf of your company, but you should treat the authentication code as a sensitive company credential. Companies House says the code should be treated with the same care as a bank card PIN. Anyone who knows it may be able to change company details online.

If your accountant has the code, make sure you are comfortable with their access. If you stop working with an accountant or an employee who knew the code leaves your business, consider changing the authentication code. Companies House specifically recommends changing the code if it is known to someone who is no longer authorised to file for the company.

What If Someone Else Has My Authentication Code?

This is more serious than simply forgetting the code. If you believe the code has been disclosed to someone who should not have it, change it. Companies House allows you to change or cancel the company authentication code through WebFiling.

For example, suppose a previous accountant still has your company's authentication code. Even if you trust the accountant, they may no longer be authorised to act for the company.

Changing the code prevents the old code from continuing to provide online filing access. You should also consider using Companies House's PROOF scheme, which is designed to provide additional protection against certain unauthorised paper filings.

What If I Think Someone Has Used My Code?

Check your company's Companies House filing history. Look for unexpected changes involving:

• Directors
• Registered office
• Company name
• Share information
• Persons with Significant Control
• Confirmation statements
• Other company filings

Companies House also provides a free Follow service that can send email alerts when information is filed for a company you follow. This is a useful preventative measure, particularly for companies managed remotely. If you see a filing that you did not authorise, contact Companies House promptly and investigate the issue. Do not assume an unexpected filing is merely an administrative error.

Should I Change My Authentication Code After Receiving a Replacement?

You do not have to change it simply because you requested a reminder. However, changing it can make sense if:

• You believe the previous code was compromised.
• A former accountant knew it.
• A former employee had access.
• You shared it with someone who no longer works with the company.
• You want a code that your current authorised filing team can manage securely.

Companies House allows companies to change their authentication code through WebFiling. You can choose a more memorable code, but Companies House recommends that it should not be easy to guess. If you change it, remember to tell anyone who legitimately files for the company. The old code will no longer work once the change takes effect.

What Happens If My Filing Deadline Is Approaching?

Act immediately. This is particularly important for:

• Annual accounts
• Confirmation statements
• Director changes
• Registered office changes
• Share-related filings
• Other statutory submissions

Some online filing services require the authentication code. For example, Companies House requires the company authentication code for certain confirmation statement services. If you wait until the filing deadline and then discover that the code needs to be posted to an inaccessible address, you may not have enough time.

A better compliance habit

Request or verify access to your authentication code well before important filing deadlines. Keep the code securely recorded, but do not store it in an openly accessible document or share it unnecessarily. For companies managed by multiple people, establish a simple internal process for determining who is authorised to file information.

Does the Authentication Code Expire?

The authentication code is a continuing company credential rather than a one-time verification code for each filing. Companies House says the same authentication code can be used for the company's online filings through its supported services.

However, the code can be changed or cancelled. If it has been changed, the previous code will no longer be the active code for filing. This is another reason to avoid relying on an old password manager entry, accountant's records or incorporation paperwork without checking that the code is still current.

Authentication Code vs GOV.UK One Login

Companies House has introduced significant changes to online access, including the use of GOV.UK One Login. This can make the terminology confusing. GOV.UK One Login helps authenticate the individual using Companies House services. The company authentication code, however, remains a credential associated with the company and is used to authorise company filings.

Companies House's online filing guidance says WebFiling users have been required to connect their WebFiling account to GOV.UK One Login, while the company authentication code remains relevant to confirming authority to file for the company.

In practical terms: Your personal identity verification does not automatically replace your company's authentication code. You may need both, depending on the Companies House service and filing you are using.

A Simple Recovery Checklist

If you have lost your Companies House authentication code, use this checklist.

1. Confirm the company number

Make sure you have the correct company number before starting the recovery process.

2. Check your registered office

Confirm that Companies House has the correct registered office address.

3. Check with your mail provider

If you use a registered office service, ask whether Companies House correspondence has arrived.

4. Request the code

Use the Companies House WebFiling process to request an authentication-code reminder.

5. Allow enough delivery time

Companies House says delivery can take up to 10 working days.

6. Consider the home-address option

If you cannot access the registered office, check whether you qualify to have the code sent to an active officer's home address.

7. Check your filing deadlines

Do not let a missing code cause an avoidable late filing.

8. Secure the replacement code

Treat it as a sensitive company credential.

9. Change the code if necessary

If the old code may have been compromised, change it once you regain access.

10. Monitor the company's filing history

Consider Companies House email alerts so that unexpected filings can be identified quickly.

Frequently Asked Questions

What should I do if I lose my Companies House authentication code?

Request an authentication-code reminder through Companies House WebFiling. The replacement is normally sent by post to the company's registered office and can take up to 10 working days.

Can Companies House send my authentication code by email?

No. Companies House does not send authentication codes by email or provide them over the telephone.

Can I get my authentication code sent to my home address?

In certain circumstances, yes. Companies House has a service that allows an authentication code to be posted to an active officer's home address instead of the registered office. Eligibility restrictions apply.

Is my Companies House authentication code the same as my personal code?

No. The company authentication code belongs to the company and authorises online filings. A personal code belongs to an individual and is associated with Companies House identity verification.

How long does a replacement authentication code take?

Companies House currently says it can take up to 10 working days for the code to arrive by post.

Can my accountant use my company's authentication code?

An accountant can file on behalf of a company when appropriately authorised, but the authentication code should only be shared with people you trust and who are authorised to file for the company.

What if my former accountant still has the authentication code?

Change the company authentication code. Companies House specifically recommends changing it when someone who is no longer authorised to file for the company knows the code.

What if I suspect someone has used my authentication code?

Review the company's Companies House filing history and contact Companies House if you identify an unauthorised filing or other suspicious activity. You should also change the authentication code if it may have been compromised.

Can I file Companies House documents without the authentication code?

Some alternative filing methods and services may be available depending on the document and circumstances, but many online company filings require the authentication code. If you have lost yours, requesting a replacement promptly is generally the simplest route.

Conclusion

Losing your Companies House authentication code is inconvenient, but it is not a reason to panic and certainly not a reason to form another company. The authentication code is a security credential used to authorise online filings for your company. If you have lost it, Companies House provides a process for requesting a reminder, normally sent by post to the company's registered office. Delivery can take up to 10 working days, so it is sensible to deal with the issue before an important filing deadline.

If you cannot access your registered office, an active officer may be able to use Companies House's home-address service, subject to eligibility requirements. Most importantly, protect the code once you regain it. Companies House treats the authentication code as equivalent to a company officer's signature for online filing, and anyone who has the code may be able to make changes to the company's information online.

For global founders managing UK companies remotely, reliable registered-office and mail-handling arrangements can therefore be an important part of ongoing company administration. IncorpUK, as a UK company formation and management platform for global founders, operates within this wider post-incorporation infrastructure alongside accountants, tax advisers and other professional services. The key takeaway is simple: request the code early, make sure your registered office can receive it, never share it unnecessarily, and change it if you believe it has been compromised.