Internal government data indicates that Home Secretary Shabana Mahmood's proposed changes to settlement rules for migrants — which would require most people to wait 10 years rather than five to qualify for permanent residency — will save approximately £600 million, far short of the £10 billion figure she publicly cited. Analysis by economist Jonathan Portes of King's College London, based on figures from the Migration Advisory Committee (the UK government's independent body that advises on immigration policy) obtained via a freedom of information request, found that migrants are net contributors to public finances for at least the first two decades after arrival, with negative fiscal impacts typically only emerging after around 40 years. Critics, including the Labour-aligned think tank IPPR and several Labour MPs, have called for parliamentary scrutiny of the proposals and warned that any modest savings could be outweighed by the economic costs of deterring skilled workers from settling in the UK; the Home Office has defended the £10 billion figure as an illustration of the lifetime cost of the cohort, rather than a savings projection.