A Home Office policy that gave migrants as little as 72 hours notice of their impending deportation is unlawful because it created "an unacceptable risk of interference with the right of access to court", the Court of Appeal has ruled.
Medical Justice took legal action over the policy, under which migrants were given between three and seven days notice that they might be removed from the UK at some point during the next three months without further warning.
The campaign group argued that it would be impossible for those who do not already have a lawyer to obtain one in the notice period, meaning the policy posed "a serious threat to the rule of law".
Last September, the High Court rejected Medical Justice's claim that the Home Office had "curtailed or removed the right of access to court to challenge [its] decisions". Mr Justice Freedman found the Home Office had included "a whole series of safeguards" in the policy, which he said "operate so as to preserve rather than to impede access to justice".
But Medical Justice took its case to the Court of Appeal, which unanimously ruled on Wednesday that the policy was unlawful because it led to "a real risk of denial of access to justice".
Lord Justice Hickinbottom, sitting with the Lord Chief Justice, Lord Burnett, and Lord Justice Coulson, found that "whether an irregular migrant is removed before he or she has had an opportunity to obtain legal advice and apply to the court is a matter of pure happenchance".
He found that the policy, which has been suspended since March 2019 pending the outcome of Medical Justice's case, was therefore "arbitrary" and unlawful.
Lord Justice Hickinbottom said the policy "incorporated an unacceptable risk of interference with the right of access to court by exposing a category of irregular migrants ... to the risk of removal without any proper opportunity to challenge a relevant decision in a court or tribunal".
In a separate judgment, Lord Burnett said: "There is no escaping the conclusion that the policy puts irregular migrants at risk of removal immediately following an adverse decision made, or notified, during the removal window which thus deprives that group of a proper opportunity to challenge the decision before removal."
In a statement after the ruling, a Medical Justice spokesman said: "One of our society's most precious treasures is access to justice. Chillingly, away from the public gaze, this policy denied that fundamental right on a massive scale, causing serious harm to extremely vulnerable people and risking life.
"It was effectively a shortcut to removal. Quashing the policy brings us back towards equal access to justice for all.
"Many of our sick clients were subject to 'removal windows' – we didn't know if they would still be in the UK from one day to the next. Clients we have managed to remain in contact with have described terrible consequences. Others have not been heard of again.
"Cases where people are removed from the UK without access to legal representation are particularly concerning as they are unlikely to be known about by any independent organisation, making it difficult to know the true extent of the policy's impact."
Rakesh Singh, of the Public Law Project, which represented Medical Justice, said: "This is a case about access to justice, one of the fundamental values of the British constitution.
"The 'removal windows' policy shut people out of the legal process. It meant that when mistakes were made, people could not access the court to put things right and led the Home Office to remove people with a right to be here – including a number who were caught up in the Windrush situation.
"Removing people in this way caused terrible injustices and placed many individuals and families in danger and into hardship, unnecessarily and unjustly."
A Home Office spokesman said: "Our immigration and asylum system is fundamentally broken, and we are determined to introduce a new system that is fair, firm and will expedite the removal of those who have no legitimate claim for protection."