The PCS, which represents around 80 per cent of Border Force officials, and Care4Calais, a refugee charity, announced on Wednesday that they were taking the Home Office to court over the policy and had filed an application for a judicial review.
The judicial review will challenge the lawfulness of the policy, which the PCS argued “contravenes international law and is morally reprehensible”.
Even if the court application is unsuccessful, the union has not ruled out industrial action and officials refusing to carry out the pushbacks.
Mark Serwotka, general secretary of the PCS, said: “The legality of the pushbacks policy is in serious question, and it is right that the court decides whether it is unlawful to turn back Channel boats.
“We cannot have a situation where our members could be open to potential civil and criminal action for implementing a policy that they do not agree with and know is not safe.
“Although we are hoping for a positive outcome from the legal proceedings, people should be in no doubt PCS strongly opposes this policy, on moral and humanitarian grounds, and we will not rule out industrial action to prevent it being carried out.”
The union said its members who work for Border Force are “deeply concerned” the policy will be impossible to implement in a safe way, due to difficulties in assessing whether a boat at sea can be safely turned around.
Members may also be exposed to personal civil or criminal liability if the policy is deemed unlawful, the union claimed.
Clare Moseley, founder of the refugee charity Care4Calais, said: “The proposed policy deprioritises the UK’s duty under domestic and international law to save lives at sea.
“It is for good reason that this duty is a cornerstone of International maritime law. If eroded, I fear it will enable the UK to devalue lives at sea.
“It risks opening the gates to the horrific scenes we are seeing in the Mediterranean.”
The Home Office continues to explore various options in its bid to halt crossings by thousands of people from France aboard small boats.