The P2030 programme is designed to create fiscal space for some of the national priorities that are otherwise unreachable in the current system. With taxes configured per this report, an additional £38B of revenues are generated that have not been allocated to any other policy in the programme.
The P2030 does not require any new borrowing and covers capital improvements to transport, housing, food, energy, and water out of revenues. So the 1.4% of GDP additional fiscal space is real.