His subversive reflection was that centre-left parties had been “squeamish” about saying things that were “clearly true” about controlling borders.
The solution was digital ID – long hinted at by government, now confirmed.
The justification is twofold. One, that it will make it easier to crackdown on illegal working, reducing the attractiveness of the UK to those crossing the Channel in small boats.
And two, that it will make everyday life easier, from proving your address when you go the council skip, to registering for benefits.
Other parties are united in their opposition. The Conservatives and Reform say it will not stop illegal working.
The Liberal Democrats and others raise concerns about privacy and civil liberties.
There is already confusion about what exactly the primary motivation is.
The former Labour Home Secretary Lord Blunkett criticised the reforms for not being strong enough.
“I’m mystified because we are living in an era of conviction, high-profile, shake-the-tree politics, and this looks like a whimper,” he told BBC Radio 4’s, World At One.
“Why aren’t our people coming out and arguing this case full on? We need conviction politics now and we need it urgently.”
None of this will be quick. There will be an official government consultation now, before legislation is brought to parliament. Then if it eventually becomes law, there will be a period of implementation.
Despite those calls for extra toughness, this has the potential to be a dividing line for Labour on something it believes the public support, despite more than a million people signing a petition against the idea.
But also – if it eventually becomes law – this could be a defining legacy for Sir Keir and this Labour government.