British citizenship after ILR — the naturalisation requirements

Getting ILR isn't the finish line if you want to become British — it's the start of a new, shorter countdown with its own residence and absence rules that are not the same numbers as the ones you just cleared for settlement. Mixing the two up is the most common mistake we see.

Last verified: 2026-07-04 against gov.uk/apply-citizenship-indefinite-leave-to-remain.

The 12-month wait — unless you're married to a British citizen

You must hold ILR for 12 months before you can apply to naturalise (Form AN) — with one significant exception: if you're married to (or in a civil partnership with) a British citizen, this 12-month wait is waived. You can apply as soon as you have ILR. If that applies to you, don't wait out a 12-month clock you don't actually need to observe.

The residence and absence rules — different numbers from ILR

This is where people carry over the wrong figures from their ILR application. For naturalisation:

You need 5 years of UK residence immediately before your application date (or shorter if the marriage exception above applies to your situation — confirm your own case rather than assuming).
Maximum 450 days absent across the whole 5-year period — not the 180-days-per-rolling-year rule from ILR. A pattern of travel that was perfectly fine for your ILR absence check can still be too much for this cumulative 450-day cap, because the two rules measure completely different things (rolling 12-month maximum vs. a flat total over 5 years).
Maximum 90 days absent in the 12 months immediately before you apply.
You should have been physically in the UK exactly 5 years before the date your application is received — GOV.UK notes an application can be refused on this point unless a special circumstance applies (their examples: health reasons or travel restrictions).

Run your own numbers before assuming your ILR absence history "already proved" you're fine for this — the two calculations aren't interchangeable.

Good character

You must be "of good character," assessed against Home Office naturalisation guidance, and you must not have broken UK immigration law during your residence. This is a judgement the caseworker makes on your specific history — it isn't a checklist you can self-certify against.

Life in the UK test — don't retake it if you don't have to

If you already passed the Life in the UK test for an earlier application (including your ILR application), you don't need to sit it again — the same pass carries forward.

English — a separate requirement, assessed on its own

This one catches people out. English is a separate limb from the Life in the UK test, assessed independently — passing (or being exempted from) one doesn't automatically exempt you from the other. If you weren't asked to re-prove English at your ILR stage (common on work routes, where it was assessed earlier in your visa history), check specifically whether that same evidence, or the same exemption, is accepted for the naturalisation application — the exemption categories aren't guaranteed to line up exactly between the two applications.

Cost

Application fee: £1,709, plus a £130 citizenship ceremony fee — £1,839 total (verified against GOV.UK on 2026-07-04). You attend a ceremony after approval; citizenship isn't complete until you have.
If you're naturalising alongside registering a child via MN1, use the Family Immigration Cost Planner to see both costs together.