A British court on Wednesday ruled that parts of an interior ministry scheme to protect the status of millions of Europeans living in the UK is unlawful, as a result of wrongly interpreted post-Brexit rules.
Rights' groups advocating for EU and other European nationals welcomed the High Court judgement, but the ministry promptly said it planned to appeal the case brought by an immigration watchdog agency.
Under the government's "EU Settlement Scheme", some five million Europeans have been granted temporary (pre-settled) or permanent (settled) status, with ministers hailing it a success.
But critics argue the policy is incompatible with the UK-EU Brexit deal, because it will automatically make nearly 3 million people given pre-settled status "illegal overstayers" if they fail to make another application.
In his ruling, judge Peter Lane agreed that if the UK government's interpretation of the law was correct, "a very large number of people face the most serious uncertainty".
He concluded that the interior ministry had incorrectly interpreted the law stemming from the 2020 withdrawal agreement between London and Brussels, as it could potentially deprive applicants of their rights.
In response, junior interior minister Simon Murray insisted the settlement scheme "goes above and beyond our obligations under the withdrawal agreement".
He said it protects EU citizens' rights and gives them "a route to settlement in the UK".
"We are disappointed by this judgement, which we intend to appeal," Murray added.
The case was brought by the Independent Monitoring Authority, a watchdog set up by the government to guard EU citizens' rights in the UK after Brexit.
The European Commission and the3million, a grassroots organisation representing EU citizens in the UK, also supported it.
Monique Hawkins, of the3million, said the ruling would help "protect vulnerable citizens who are granted pre-settled status under the EU Settlement Scheme, and who could lose their right to work, rent, travel, benefits, healthcare and more".
"We are pleased that the judge agrees with the3million that the point of the EU Settlement Scheme is to create a clear distinction between those who are beneficiaries of the Withdrawal Agreement and those who are not," she added.
"Once a beneficiary, people cannot lose their rights just by forgetting to make a second UK immigration application -- the Withdrawal Agreement does not allow it."