Shabana Mahmood’s retrospective action on immigration could undermine trust in government

Shabana Mahmood’s plans to apply changes to settlement rules for those who are already living in the UK will, if enacted, have far-reaching consequences. The most significant of these are changes to the waiting period for indefinite leave to remain (ILR). Under these plans, migrants who arrived in the UK since 2021, expecting to be granted indefinite leave to remain  ⁴³ This is the permanent right to live, work and study in the UK, and access state support.  five years after their arrival date, may face a further five to 10 years before they can permanently settle.

The home secretary says these changes will produce significant savings for the exchequer as migrants will spend more time unable to access benefits or state support – though the savings figures she cites have received heavy criticism.  ⁴⁴ https://www.theguardian.com/uk-news/2026/apr/13/mahmood-migration-reforms-fraction-claimed-savings  MPs, unions and civil society have argued that changes for those already on routes to settlement move the goalposts, and violate basic expectations that migrants rely on when making decisions to come to the UK.  ⁴⁵ https://www.bbc.co.uk/news/articles/cy514kv2vzro   ⁴⁶ https://www.ft.com/content/8404071c-c225-4edd-ba2f-e018a8d92590?syn-25a6b1a6=1

Retrospective action is not uncommon in policymaking

An action is retrospective when it applies to past events, conduct, or legal situations, rather than only to things that happen after the law is enacted.

There are several instances – across different policy areas – where government has enacted changes that have had a retrospective effect. These include changes made to capital gains tax on disposable assets; inheritance tax; landlords’ and leaseholders’ rights; and the state pension age. Governments have also regularly changed the law to make people liable for tax retrospectively, under the 1978 “Rees Rules”, to counter aggressive avoidance of taxation through ‘loopholes’.  ⁴⁷ https://commonslibrary.parliament.uk/research-briefings/sn04369/   

These changes, while often unpopular, are procedurally normal; retrospection is expected, managed and justified as protecting the public interest.

Some types of retrospective action are more controversial and associated with heightened legal risk

A second category of retrospective action – changes which don’t just impact financial liabilities or tax arrangements – is far rarer and more controversial.

For example, in 2013, the Cameron government legislated to prevent claimants recouping benefits that the Court of Appeal previously found had been wrongly withheld from them. The retrospective legislation used by the government was found to be in contravention of Article 6 of the European Convention on Human Rights, and the Lords Constitution Committee described it as a “cardinal principle” that people should not be punished for following the laws at the time of an offence.  ⁴⁸ https://committees.parliament.uk/committee/172/constitution-committee/news/180724/jobseekers-bill/  The government introduced a Remedial Order in 2020 to correct for the act’s contravention with the ECHR, providing claimants some routes to challenge sanction decisions.

Types of retrospective action involving settlement rights are even more sensitive because they affect family life, employment and legal security. In a case analogous to Mahmood’s reforms, the Brown government attempted to restrict settlement rights for migrants who had entered the UK under the Highly Skilled Migrant Programme, with retrospective effect. This decision was challenged successfully by a group of affected migrants, with a high court judge, at judicial review, stating that changing the rules would “give rise to conspicuous unfairness and an abuse of power”.  ⁴⁹ https://irr.org.uk/article/legal-reversal-on-highly-skilled-migrants/  Following this judgement, the Home Office provided fee refunds and preserved the original rights of the migrant group. When the government attempted to comply with the 2008 ruling only regarding visa extensions, while still forcing migrants to wait five years for ILR, it was again challenged successfully at judicial review.  ⁵⁰ https://www.charlesrussellspeechlys.com/en/insights/quick-reads/102kbau-retrospectively-changing-indefinite-leave-to-remain-rules-for-those-currently… This case law has become the bedrock for migrant protection against sudden, retrospective changes to migration law, where government “moves the goalposts”.  

The government’s announcements on settlement are controversial because of the sheer scale, scope and complexity of changes. Analysis suggests that two million migrants  ⁵¹ https://www.gov.uk/government/news/biggest-overhaul-of-legal-migration-model-in-50-years-announced , including 300,000 children  ⁵² https://www.theguardian.com/uk-news/2026/feb/09/children-settled-status-home-office-plans-ippr , will be impacted, and some experts argue that there are likely to be significant spill-over effects in the form of worsening inequality, poverty, and in-work exploitation.  ⁵³ https://ukandeu.ac.uk/unsettled-status-the-policy-and-politics-of-indefinite-leave-to-remain/   ⁵⁴ https://committees.parliament.uk/publications/52138/documents/290281/default/

Retrospective action has (largely) avoided controversy when there has been a presumption of reasonableness and precedent. Reasonableness is a normative judgement: for example, it is reasonable, many argue, to change pension expectations because government does this through a standardised and lengthy process, with consultation, and these changes happen often. But, in the case of these proposed immigration changes, precedent, if anything, points in the opposite direction – suggesting that Shabana Mahmood’s plans will face serious pushback in the courts.

Enacting policy in a rush with limited parliamentary scrutiny will store up problems for the future

It also seems parliament will have virtually no say on these plans.  ⁵⁵ https://committees.parliament.uk/publications/52138/documents/290281/default/  The home secretary has wide discretion to change visa and settlement rules through secondary legislation using statements of changes, with no vote required in parliament.  ⁵⁶ Most changes to the immigration system are done through changes to the ‘immigration rules’. These rules are made and amended through secondary legislation, using powers established under the Immigration Act 1971. These are scrutinised by Parliament in the same way as other secondary legislation subject to ‘negative’ procedure, where there are no timetabled debates or votes as there are with primary legislation. If Parliament wants to debate a change, it must put forward a motion to annul, known as a ‘prayer’. [https://www.instituteforgovernment.org.uk/sites/default/files/publications/IfG-Migration-After-Brexit_4.pdf]  The Home Office therefore plans to begin implementing these changes imminently to show that it is “gripping” the problem. But change of this scale should require proper consultation, committee scrutiny and consent by vote in parliament.

The Home Office can say that it has tested the changes through public consultation – receiving a record number of responses. However, as we’ve recently argued, consultations “too often become performative, compliance exercises with no attention paid to the issues revealed.” It is unclear, given the rapid pace that government is moving, how this volume of responses have been analysed and fed into the changes.

Action undermining people’s ability to plan undermines the principles of fairness that are foundational to British common law and, ultimately, good governance. As such, retrospective changes should meet a very high bar, in terms of ensuring the changes are both desirable and implementable, properly tested with stakeholders, and scrutinised by parliament. The Home Affairs Select Committee has said that “it is more important to get changes right than to implement them quickly.” The Institute has argued previously that the Home Office could benefit from its own version of the DWP’s Social Security Advisory Committee, which focuses on the operational feasibility of policy.

In attempting to grip the immigration issue, Shabana Mahmood is no doubt keen to demonstrate changes to the system which allow Labour to fend off criticism from political parties to its right. But retrospective action of this kind, implemented at quick pace and with no involvement from Parliament, seems likely to both heighten legal risk for government and undermine trust in government.