The Office for Budget Responsibility has now become a serious irritant to this government and has disrupted Rachel Reeves’ plans for her Spring Statement. Is this because, in the words of economist Daniel Susskind in an FT opinion piece, it has become “a victim of its own success” in terms of how seriously its word is taken as policy law?

Mutterings about the overweening fiscal regulator used to be a favourite theme of Conservatives, pre-election, even after Liz Truss’s attempts to sideline it failed so spectacularly in the “mini” Budget of 2022.

But now, due to extra cuts to welfare on top of painful cutbacks in secretary Liz Kendall’s green paper, the Labour benches may take up the same theme — calls may grow to try to decouple policymaking from at least the OBR timetable, if its forecasts are determining the substance and timing government policy decisions to this extent.

As Susskind writes, the chancellor as she prepped for today’s statement was hemmed in not so much by the (mysterious, he says) reality of what will drive economic growth but by what, crucially, governs the forecasts.

“Reeves is best advised not to do what she believes will drive growth, but to look instead at what the OBR assumes drives growth. Then she must simply do as much of that as she can, given her fiscal constraints, so the forecasts are better.”

If welfare cuts are both unpopular and possibly not a policy pursued for the right reasons, this will be a serious headache for Reeves and Kendall in the coming months, rather than just a few wobbles today.