Getting a UK citizenship will give the advantage to several benefits. The Form AN is used for apply for UK citizenship. Start your online UK citizenship application today. UK Immigration Centre helps you prepare British Naturalisation Application Online with the Form AN. Fast & Easy Steps. Check your eligibility for FREE to become a UK citizen today! Call Us @ (020) 3514 1471. Disclaimer: UKImmigrationCentre.co.uk is a private entity and is not affiliated or approved by any government agency. We are not a law firm and don’t provide attorney’s services.