By Paul Brand: ITV News
I've had it confirmed to me this morning that around 20 Conservative MPs, apparently led by MP Andrew Percy, have written to the Chancellor concerned about the recent cuts to disability benefits.
The letter was sent the day before the Budget, but a source has told me that many Conservative MPs are even more concerned now that the contents of the Chancellor's red box have been delivered.
One MP said the Chancellor should have raised fuel duty rather than cutting disability benefits, with concerns about how the narrative plays out to voters.
Conservative backbenchers are convinced that they could get far more than 20 signatures if they canvassed support against the measure today.
Labour say around a third of George Osborne's savings will come from cutting benefits to disabled people, although the Chancellor insists the overall funding will actually rise.
It seems a backbench rebellion, similar to the one over working tax credits last year, could be brewing for the Chancellor.