There are two routes that can lead to British citizenship after 3 years of continuous residence in the UK. The most common is Indefinite leave to remain as a spouse and less common is through the Global talent visa. You must be 18 years of age or above, must have lived in the UK for at least 3 year prior to application. An exception is that, if your partner has died, the spouse route is not an option for you or if you have spent more than 270 days outside the UK, then your citizenship application is refused.

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