Sir Keir Starmer’s “one-in-one-out” migrant returns deal with France has suffered another humiliating setback after the High Court temporarily blocked the deportation of an Eritrean man. The Government’s returns agreement has yet to send any migrants back to France since it came into force last month.

The High Court granted the Eritrean man a “short period of interim relief” on Tuesday ahead of his deportation, which had been scheduled for a 9am flight on Wednesday. Lawyers acting on the man’s behalf said the case “concerns a trafficking claim”.

The man alleges he has a gunshot wound in his leg, claims he is vulnerable and faces a risk of “destitution” in France. The Home Office defended the case, saying it was reasonable to expect the man to claim asylum in France.

The legal wrangling has prompted doubts as to whether or not Sir Keir’s migrant deal can actually get off the ground.

Technology Secretary Liz Kendall defended the deal during a round of media appearances on Wednesday.

She told Times Radio she would not comment on “operational details”, but said: “This is one person. It is not going to undermine the fundamental basis of this deal. This decision is disappointing, but it won’t prevent the rest of that deal going ahead.”

Conservative Party leader Kemi Badenoch said her message to ministers was “we told you so”. Shadow Home Secretary Chris Philp called the returns scheme is “another failed gimmick from this weak Government”.

He added: “On Monday I told the new Home Secretary in Parliament that unless they disapply the Human Rights Act for immigration cases, their meagre returns deal would collapse in court. She refused to listen, and here is the predictable result.”

Reform UK leader Nigel Farage claimed the Government was “not telling the truth” about its immigration plans, adding: “Even if the policy worked, one in, one out, and with another one in, still means plus one for everyone that crosses the Channel.”

The latest setback comes after reports suggested the first flights planned to remove those back to France under the deal departed without any migrants on board on Monday and Tuesday.

On Tuesday, Downing Street denied the returns scheme was a “shambles” and rejected suggestions the postponement showed ministers were powerless in the face of the courts.