An application submitted today may take longer than eight months for naturalization, adult registration could take up to three and a half months and close to eight months for registration of minors. Other registrations could take slightly more than four months to process, two months for renunciations and 10 weeks for right of abode applications.
The average time for a decision for all applications is seven and a half months. Note that these are average times only and some of them might take even longer.
More information about UK immigration and Naturalisation.