Very interesting that the OBR have chosen to note that (highlighting my own):
There have been, and will continue to be, wider operational changes within HMRC and across Government that are likely to affect the public finances. For example, reductions in administrative spending in other areas of HMRC could lead to less tax revenue being collected. We have not been presented with costings for such changes. Therefore, taken in isolation the costings for the specific operational changes in the Treasury’s policy decision table are potentially unrepresentative of the impact on wider operational changes across Government.
What does this mean? My reading: that the Government are keen to claim they are investing more resources in HMRC, but have declined to give the OBR numbers as to significant operational cuts which HMRC is currently experiencing, which the OBR reckon will reduce the amount of tax collected.