The UK government has dropped plans to turn back people crossing the English Channel just over a week before they were due to be challenged in court.
Campaigners say the policy, which would allow Border Force patrols to intercept boats and take them back to France, is inhumane and a risk to life.
The PCS civil servants’ union called the government’s change of mind a “humiliating climbdown”.
But the Home Office said ministers were “unified” in wanting to stop crossings.
The government has dropped the policy ahead of the High Court challenge, meaning the so-called “pushback” tactics are not currently in use.
Last week ministers announced separate controversial plans to send some asylum seekers to Rwanda in a bid to reduce the number of migrants crossing the Channel.
At the same time it was revealed the Royal Navy would take charge of responding to small boats in the Channel alongside Border Force – although the military said it would not be using “push back tactics”.
The PCS and the campaign groups Care4Calais, Channel Rescue and Freedom from Torture have argued that the Border Force does not have the legal authority to push the vessels back, and that doing so would infringe on migrants’ human rights.
Following the Home Office’s decision, they have now withdrawn their judicial review claims, which had been due to be heard on 3 May.
PCS general secretary Mark Serwotka said: “This humiliating climbdown by the government is a stunning victory for Home Office workers and for refugees.
“PCS is proud to have brought this legal action alongside refugee groups in order to prevent this morally reprehensible and utterly inhumane proposal from ever seeing the light of day. There is little doubt that lives have been saved.”
But a Home Office spokesperson said: “The entire government is united in our efforts to prevent these lethal crossings and break the business model of the criminal gangs exploiting people.
“It is right that we consider all safe and legal options to stop these unnecessary journeys, including turning boats around.”
They added: “As we have set out previously, this tactic fully complies with both domestic and international law. However, there are extremely limited circumstances when you can safely turn boats back in the English Channel.”
Last year, the government authorised Border Force officials to use the tactic of turning back boats containing migrants – but only in limited circumstances.