The tax hike will see the Class 1 National Insurance contributions (NIC) rate rise to 15% a year from the current 13.8%, and the halving of the starting rate for paying employer national insurance (NI) from a £9,100 secondary threshold to only £5,000 per year.

The cut in the threshold will see hundreds of thousands of part-time workers dragged into employers’ NI for the first time. This will hit retail and hospitality sectors hard, with major supermarkets, for example, projecting multimillion pound hikes in employment costs.

To support small businesses, the government has increased the employment allowance from £5,000 to £10,500 from 6 April, and removed the £100,000 threshold, expanding this to all eligible employers.