"...It’s partly a performance, the same iron chancellor routine adopted by Gordon Brown in 1997, when he broke Labour hearts on single-parent benefits and stuck to his promise to stay within Tory spending limits for two years"
"

He's referring to the despicable Blair's babes thing whose first vote was on policy designed to further impoverish single mothers so I suppose it fits a ritual pattern of "performative" politics which right wing Labour feels a need to act out on stage.

- When you enter the halls of power you must pick a weak victim and sacrifice them to prove to the God of Capitalism that you are a true and ruthless believer.