Certificate of Naturalisation: Everything You Need to Know About UK Citizenship Documentation

Get your Notarised and Apostilled document with us. Fixed fee service.

What is a Naturalisation Certificate?

A Naturalisation Certificate is the official document issued by the UK government confirming that someone has become a British citizen through naturalisation.

UK citizenship certificates:

Proves proof of citizenship.
Is used in:
immigration laws
right of abode
residence permits.
UK visas and Immigration processes
passport applications
matters in relation to immigration status.
other legal processes
Naturalisation is the legal process by which a non-British adult becomes a British Subject.

What about Certificates of Registration are they the same?

No, a Naturalisation Certificate should not be confused with a Certificate of Registration which is issued when someone becomes a British citizen through registration rather than naturalisation.

This is commonly when children of British nationals have a legal entitlement to be a citizen of the UK. Registration certificates are mainly issued to children of parents who came from British Overseas Territories.

(See below for an explanation on how to apply for a British nationality certificates.)

Here’s the deal.

Our Service – Certified Copy of Original Document and Apostille Service

We offer a service specifically tailored to Spanish nationals wishing to maintain their Spain dual citizenship. (OK, it’s open to everyone but we know from experience that Spanish people need this service more than most).

Including our fee, VAT and FCDO fee.

£200

We must have sight of the original document in paper form. We will produce a certified copy signed by our Notary Public.
We will use the online service to make an application for Apostille with the FCDO Legalisation Office, take the duplicate certificate (duly notarised) there by hand, return and pick up.
Make available for you to collect or have it dispatched to your permenant residence or office.

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Pro Tip for Spain Dual Citizenship

If a Spanish national naturalised as British, but didn’t notify the Spanish authorities, they might still be treated as Spanish — or in some cases, be at risk of losing Spanish citizenship under Spanish law (though this is rarely enforced).

So the naturalisation certificate is crucial to show dual nationality was acquired lawfully and declared properly.

Visit our Spain Dual Citizenship page for a guide on how you do this.

If you need your Certificate of Naturalisation notarised, get in touch now.

spanish dual nationality | Notary Public London — Spanish dual nationality

How to obtain a Naturalisation Certificate

You can obtain a naturalisation certificate when you meet residency requirements and additional requirements.

If married to or in a civil partnership with a British citizen for 3 or more years

Having indefinite leave to remain or Settled Status under the EU Settlement Scheme
Residence requirements – not have spent more than:
- 270 days outside the UK in the last 3 years.
- 90 days outside the UK in the last 12 months.And have resided in the United Kingdom for at least twelve months before applying.

**If not married to a British citizen:**

Have lived in the UK for 5 years.
Hold ILR or Settled Status for at least 12 months.
Residence requirements – not have spent more than:
- 450 days outside the UK in the last 5 years.
- 90 days outside the UK in the last 12 months.

| Notary Public London — Obtain a Naturalisation Certificate

Other general requirements:

Pass the Life in the UK Test. Be over 18. Be of good character (no serious criminal record). Have sufficient knowledge of English, Welsh or Scottish Gaelic.(See below for an explanation on how to apply for a British nationality certificates.)

How Is a British Naturalisation Certificate Used by Spanish nationals to Prove Spain Dual Citizenship?

In many cases, Spanish nationals who naturalise as British citizens still want to maintain their Spanish citizenship — especially for property, family, or tax reasons.
But Spain often requires documentary evidence of dual nationality.

In these cases, the British passport isn’t enough. Spanish authorities want to see:

The original certificate (or a certified copy (with reference number) from a Notary Public)
Apostille from the UK Foreign, Commonwealth & Development Office (FCDO)
Sworn translation into SpanishThis combo proves when and how the person acquired British nationality — a key point for the Spanish system, which treats nationality status as a timeline.

Check out our Spain Dual Citizenship page for more.

How Is a British Naturalisation Certificate Used by Spanish nationals to Prove Spain Dual Citizenship?

Notarised Certificate of Naturalisation | Notary Public London — British Naturalisation Certificate

We offer a service specifically tailored to Spanish nationals wishing to maintain their Spain dual citizenship.

Here’s the deal

We must have sight of the original document in paper form. We will produce a certified copy signed by our Notary Public.
We will use the online service to make an application for Apostille with the FCDO Legalisation Office, take the duplicate certificate (duly notarised) there by hand, return and pick up.
Make available for you to collect or have it dispatched to your permenant residence or office.

Using Your Naturalisation Certificate for Legal and Immigration Purposes

Applying for a British passport from the UK Passport Office.
Proving your British nationality when you don’t have a passport.
Registering Spain dual nationality
Travel document – some countries may have travel requirements and a UK naturalisation certificate may allow you visa-free travel. Always check the country’s status before disembarking.
Apostille Service is needed for legalisation of a certificate of naturalisation if used overseas.

Most ask

Frequently Asked Questions

We offer a fixed fee of £200 including our fee, VAT and the FCDO Apostille fee.

Our package is a 5 working day service. If you need it quicker, let us know, we can give you our premium service which is 1-2 days.

Yes! We tailor our content services based on your business needs.

You will need an Apostille if the application you are making requires it. For example Spain Dual Nationality applications do require an Apostille.

Yes you can! Follow these steps:

Fill out Form NC
Pay the fee as per .GOV.UK website
Provide additional evidence if update personal details, including current name and previous name, (for example if you have married).