The law in the United Kingdom states a person is a UK dual national if he/she holds multiple citizenships. Normally, there isn't a restriction on nationals from Britain having dual citizenship elsewhere.
If you are a British national and you acquire another nationality, normally you will not lose your British citizenship. However, there are many things to consider beforehand and there are some existing restrictions and regulations
Dual citizenship with other nationalities
If you are concerned you may lose your existing citizenship when applying for British nationality, contact the Consulate or High Commission of the country whose nationality you already hold for further advice before applying.
However, be ready to renounce your British nationality if you are British and the country does not allow dual nationality. Also, if you have been a British national and the citizen of another country since birth, you may be required to renounce your British nationality in order to keep your other citizenship.
What to consider when traveling abroad
A State has the right to not give consular assistance to a national if they are in a country the national has dual citizenship in. For example, if you are British and Chinese, the British representative in China cannot give you consular assistance.
Because of this, if you are planning to visit your former country and not sure if you lost your nationality, ask the country's Consulate in the United Kingdom. Alternatively, if you have not lost your old nationality but want to give it up, they will also be able to assist you.
If you obtain written confirmation that you gave up your former nationality or no longer have it, or obtain a renunciation certificate before traveling abroad, this can grant you the same consular assistance which is provided to all British nationals in your former country.
Also take into consideration a married person automatically has their spouse's nationality and their children have a parent's nationality wherever they were born under many countries' international laws. Please keep this in mind when traveling, as this could also apply to your wife, husband, or children if they are traveling with you, as well.
The right of abode in the United Kingdom
It should also be noted British citizens, as well as certain Commonwealth citizens and British subjects, have the right of abode in the United Kingdom, which means they can live and work in the United Kingdom without any restrictions.
However, since December