Responding to the publication of the DPC’s full report on Tuesday night, the civil liberties group said the watchdog’s findings are “unequivocal and devastating for the Government”.

Elizabeth Farries, information rights programme manager at the ICCL, said: “By refusing to follow the DPC’s directions, the Department continues to display a very poor attitude and understanding about data protection fundamentals.

“They say they have strong legal advice in favour of the card, yet they won’t share the advice. And they have renewed their tabloid-style arguments about welfare fraud prevention, with no strong statistics or financial analysis to back these sensational claims. It is time for the Department to act in a manner that is fair, transparent, and above all else, legal. Delete our data and stop the ongoing roll out of the PSC.”

ICCL director Liam Herrick added: “This card unfairly targets economically marginalised people who depend on the State for their welfare payments. It also works in a gendered way, being a requirement for mothers collecting child benefit.

“Though the DPC report did not focus on these issues, ICCL believes that the structural inequality inherent in the card may well render it illegal.”