It gives me no pleasure to be right on this.
I mean if you have a passport then you already have an 'ID card', but I certainly don't want to take that out with me to prove my age.
My own personal thinking has evolved on the subject since I campaigned against ID cards under Blair ("no2id"). It is a question of trust and purpose. Things like the Estonian digital identity scheme do not seem to be bad in practice. The problem comes from identity checkpoints, which serve as an opportunity for inconvenience, surveillance, and negligence by the authorities.
Remember the "computer is never wrong" Fujitsu scandal? The Windrush fiasco (itself a story of identity and records)?
And anything born of an immigration crackdown is coming out of the gate with a declared intention to be paranoid and authoritarian.
For anyone outside the UK who doesn't know this reference, the UK Post Office (originally the state postal system, privatised by this time) paid Fujitsu to build a computer system. It had bugs which made it look like money was going missing. The bugs were reported, and ignored. The Post Office prosecuted employees for theft and fraud over sixteen years, ruining hundreds of lives and reputations, sending hundreds of people to prison, and causing some suicides.
It eventually came out as an investigative journalism story that the system was at fault, the people were innocent, and the Post Office knew about the bugs right from the start and had been hiding them from the police/courts. "In 2024, Prime Minister Rishi Sunak described the scandal as one of the greatest miscarriages of justice in British history" that's almost 10 years after it ended and 25 years after it started, rather too late to undo all the harm.