Allan Monks, UK economist at JPMorgan, told the Financial Times that even shaving 0.1 or 0.2 per cent from productivity would leave a hole of between £9billion and £18billion.

Expected productivity downgrade to leave Britons facing additional tax rises of at least £8bn

Allan Monks, UK economist at JPMorgan, told the Financial Times that even shaving 0.1 or 0.2 per cent from productivity would leave a hole of between £9billion and £18billion.

The Institute for Fiscal Studies (IFS) said the Chancellor is banking on making ambitious efficiencies - but that if she fails to meet her targets, she could be forced to top up…