Further pre-Budget estimates put the Chancellor's headroom against the fiscal rules at about £10bn to £20bn, either side of Newsquawk's £15bn. All are below the £23.6bn implied by the OBR's March forecast.
The Resolution Foundation says headroom could have halved to about £12bn, The Scotsman reports. Reuters puts it at around £10bn to £12bn, according to Forex.com.
The IFS says 10-year gilt yields were about 0.5 percentage points higher in September than in March. Higher debt interest alone might cut headroom by about £11bn in 2029-30, it says. In an illustrative scenario where the OBR revises up nominal earnings for two years, the IFS puts headroom at around £20bn. That is after higher borrowing costs of about £12bn and higher other spending.
Philip Shaw, in City AM, says higher yields, rate expectations and inflation could have eroded up to £15bn. He says next year's shift in the fiscal target year could add £6.7bn.
The March starting point holds up. The IFS and Shaw both give it as £24bn against the current budget rule, which is the £23.6bn figure rounded. Shaw puts March headroom against the debt rule at £27bn. None of these estimates is an OBR figure, and they have not been independently checked. The OBR publishes its own figure with the Budget on Wednesday.