British Nationality
If a naturalisation application is refused, then there is no right of appeal against the decision. You can submit a request for reconsideration of the decision using form NR if you have extremely strong grounds to believe your application shouldn’t have been refused – this is an internal review process. Alternatively, an applicant can submit a fresh application, but this does mean you will need to pay the application fee again.
The application for reconsideration of naturalisation is made using application form NR. There is no time limit set for an applicant to seek reconsideration of the refusal of naturalisation / nationality application. However, it is advised that an application for reconsideration of naturalisation / nationality refusal should be sought as soon as possible after receiving the refusal decision of the nationality application. The applicant should also pay the appropriate Home Office UKVI fee for the reconsideration application.
Whether or not your application for reconsideration can succeed depends on whether or not the reasons for refusal of the Home Office in the refusal letter are lawful or not. If the Home Office maintains decision to refuse the application following reconsideration of the naturalisation application, such decision can be challenged in court by way of Judicial Review.