Rachel Reeves could be forced to inject billions more into public services if she fails to boost productivity, economists warned last night.
The Institute for Fiscal Studies (IFS) said the Chancellor is banking on making ambitious efficiencies to improve the NHS and other services.
But it warned that if Ms Reeves fails to meet her target for increasing productivity, she could be forced to significantly top up her spending plans - potentially by up to £18billion.
The IFS estimated that the Government's spending plans imply a 2.9per cent increase in input productivity, equivalent to 1.0per cent per year.
However, the figure is more than four times faster than the estimated average annual growth rate between 1997 and 2019.
