Common Travel Area (CTA) Bilateral Framework

The CTA framework itself has no citizenship-eligibility criteria — it operates by reference to Irish citizenship and to physical journeys within the area. The citizenship-acquisition entitlement it anchors is BNA 1981 s.4AA: an Irish citizen is ENTITLED (not merely permitted) to register as a British citizen if they were in the UK at the start of the 5-year period ending with the application date, were absent for no more than 450 days across that 5 years and no more than 90 days in the final 12 months, and were not in the UK in breach of the immigration laws at any time in the 5-year period. No good-character, language, Life-in-UK, ILR-held-for-12-months, or intention-to-reside test applies under s.4AA (contrast s.6 naturalisation).

s.4AA(2) residence requirements (verbatim structure): (a) present in the UK at the beginning of the 5-year qualifying period; (b)(i) absent no more than 450 days in that 5-year period and (b)(ii) no more than 90 days in the final 12 months; (c) not in the UK in breach of the immigration laws at any time in the 5-year period. s.4AA(3) gives the Secretary of State a discretion to treat a requirement as satisfied 'in the special circumstances of a particular case' even where not in fact met. s.4AA(4) was OMITTED with effect from 2 December 2025 by the Border Security, Asylum and Immigration Act 2025 (c.31), s.42(2)(d); the current in-force s.4AA comprises subsections (1)-(3) only.

Decision-maker: the Secretary of State for the Home Department (UK Visas and Immigration / Home Office). For CTA mobility, no application is made — Irish citizens enter and reside without leave by operation of IA 1971 s.1(3) and Ireland Act 1949 s.2(1). For the s.4AA citizenship entitlement, an Irish citizen submits a registration application to the Home Office; as a registration ENTITLEMENT (s.4AA(1) 'is entitled'), a qualifying applicant must be registered, subject only to the s.4AA(3) special-circumstances discretion to relax a requirement. Registration is completed by a citizenship ceremony and oath/affirmation of allegiance (BNA 1981 s.42 / Sch.5) where required. Refusal of an entitlement registration is challengeable by judicial review (no statutory appeal lies for s.4AA registration).

As of 1 June 2026, the s.4AA Irish-citizen registration application fee is £723 for an adult and £607 for a child (unchanged on the latest fee review). This is a registration fee distinct from naturalisation: for comparison, s.6 naturalisation is £1,709 plus a £130 citizenship-ceremony fee (£1,839 to certificate; uprated 8 April 2026), with no separate biometric fee per gov.uk. The CTA mobility/residence rights themselves carry no fee, as no leave or application is required for Irish citizens to enter, reside, work, study or access services in the UK.

Three UK statutory pillars define the CTA / Irish-status framework: (i) Ireland Act 1949 (c.41), s.2(1) — the Republic of Ireland 'is not a foreign country for the purposes of any law in force in any part of the United Kingdom', so Irish citizens are not 'aliens'/'foreigners'; (ii) Immigration Act 1971 (c.77), s.1(3) — defines the Common Travel Area as the UK, the Channel Islands, the Isle of Man and the Republic of Ireland, and exempts local journeys within it from immigration control; (iii) BNA 1981 (c.61), s.4AA — the Irish-citizen registration entitlement (inserted by the British Nationality (Irish Citizens) Act 2024 (c.19), in force 22 July 2025). Implementing detail sits in SI 1972/1610.