If you are British and also a national of another country then you are a dual national. Being a dual national affects the level of consular help you receive. This page explains what assistance a British Consul may offer dual nationals.
If you have some connection with a foreign or Commonwealth country, for example, by birth, by descent through either parent, by marriage or by residence, you may be a national of that country in addition to being a British national. You should check with the authorities of any other country with which you are connected. It is for them, and not for the British Government, to determine whether you hold the nationality of their country. Acquisition of British nationality or citizenship does not necessarily cause you to lose your nationality of origin.
Some countries expect their dual nationals to travel on their national passports under certain circumstances. You should check with the authorities of your other nationality. The London addresses of foreign and Commonwealth diplomatic and consular representatives are available on this website: click here.
If you are a dual national in the country of your other nationality
If you are a British national and you are in the country of your other nationality, the authorities of your other nationality are entitled to take the view that the British Government has no standing in the matter. The British Consul will not provide consular assistance to you regardless of which passport you have used to enter the country of your other nationality. We have the discretion to make an exception to this rule if, having looked at the circumstances of the case, we consider that there is a special humanitarian reason to do so. Such circumstances might include, for example, cases concerning minors, forced marriages or capital offences. However, the assistance we can provide will depend on the circumstances and will require the acquiescence of the other state. If under the law of that country you are liable for any obligation such as military service, the fact that you are also a British national does not necessarily provide exemption and we will not intervene on your behalf on such matters. However, there is assistance that the British Consul can still provide to you in your country of other nationality.
The British Consul can...
If you are in a country of which you are not a national
You should seek consular assistance from the country on whose passport you are travelling. If you are a dual national travelling to a third country on a passport other than your British passport then you should contact your other nationality’s Embassy for assistance.
If you are travelling to a third country on your British passport
The British Consul can...
BUT Consuls cannot...