Should there be a cap on political donations to UK parties?

For a question that landed squarely inside a live Westminster row, the chamber showed remarkably little appetite for the argument that union affiliation fees complicate the picture: this was a rout, not a debate, with roughly four in five voting to cap donations regardless of what it might mean for Labour's own funding model.

The one wrinkle was generational rather than partisan. The over-55s and the youngest voters were near-unanimous for a cap, but the 35-44 group broke evenly, the only cohort not to fall in behind the majority. Men and women, meanwhile, moved in near lockstep, both siding for reform by similar margins.

The result echoes a fault line that has run through party funding since the days of cash-for-honours and the Electoral Commission's repeated calls for caps: big money in politics, whether from oligarchs, hedge funds or trade unions, tends to poll badly whoever is asked. Reform UK's funding row may have prompted the amendments, but the voters here plainly weren't inclined to carve out exceptions for their own side's paymasters.

If GMB's letter was meant to stiffen resolve against a cap, the vote suggests the argument has not travelled far beyond the whips' offices.