Does the Home Office prevent dual British citizens from travelling to the UK? 

The short answer is yes; the Home Office will not allow British citizens to return to the UK if they do not have the correct documents. The Home Office has guidance for dual citizens that explains how to ensure you have the correct documentation when travelling to the UK.   

Up until recently, it may have been possible for a dual British citizen to travel to the UK on their non-British passport if the other nationality they hold is for a non-visa country (i.e. their other nationality would not require a visa to visit the UK). However, this has changed following the enforcement of Electronic Travel Authorisation (ETA). Now, with limited exceptions, it is not possible for a dual British national to use a non-British passport to travel to the UK. So, what are the exceptions that allow a dual British national to travel to the UK without holding a valid British passport? 

Irish nationals are allowed to use an Irish passport in all cases, or an Irish passport card in some cases, to travel to the UK under the Common Travel Area arrangements between the UK and Ireland. 

If you do not have a British passport you can apply for a Certificate of Entitlement, which is a confirmation of your British citizenship that is attached to your non-British passport. You can only apply for a Certificate of Entitlement if you do not hold a British passport. Previously, the Certificate of Entitlement would be physically attached to your non-British passport and would need to be renewed each time you changed your passport. Now, the Certificate of Entitlement is issued digitally (you have an online UKVI Account), which means you only need to apply for it once. When you renew your passport, you can link the new passport to your lifetime digital Certificate of Entitlement. A Certificate of Entitlement costs £589, but if you already have a physical one attached to your passport that is still valid, you can exchange this for a free digital version. 

If you held pre-settled or settled status under the EU Settlement Scheme but have since become a British citizen, the Home Office guidance confirms you can travel to the UK on your non-British passport, as long as it is linked to your UKVI Account. If you are an EU/EEA/Swiss citizen who held EU Settlement Scheme status then you can also use a national identity card to travel to the UK, again, as long as this is also linked to your UKVI Account. Make sure when you renew your passport or national identity card that you update your UKVI Account to allow travel on the new document. 

The Home Office has put in place a limited mitigation that permits carriers to allow you to travel to the UK if you have an expired British passport. To take advantage of this, all the following conditions must be met: 

• Your British passport was issued from 1989 onwards;
• The non-British passport you are travelling on is from a country that is eligible for an ETA (i.e. your other citizenship is a non-visa nationality for the purpose of the UK Immigration Rules)
• The personal details on your expired British passport and your non-British passport match

Note that the Home Office does not require carriers to permit you to travel using the expired British passport, so you will need to check with individual carriers if they will permit you to do so. 

In some situations, the Home Office may issue you an emergency travel document, which allows you to travel to the UK from abroad one time only. All the following conditions must be met: 

• You are outside the UK 
• You need to travel within 6 weeks 
• Your British passport has been lost, stolen, damaged, is full, has recently expired or is with HM Passport Office or a foreign embassy 
• You cannot renew or replace your British passport from abroad before you travel 
• You have had a valid UK passport that was issued on or after 1 January 2006 (if your last valid passport was issued from before this date you may still be issued with an emergency travel document if there are compelling reasons). 

It costs £125 to have an emergency travel document issued. It is also important to check the entry and exit requirements of the country you are travelling from, as well as any other countries you are passing through, to ensure you can complete your journey (and return to the country on the emergency travel document if that is your intention).