Those earning high salaries will pay proportionally less national insurance than those on middle incomes when the rate rises in April.
Research by Income Tax Calculator UK shows that people earning £100,000 will pay seven per cent of their overall salary to NI - the same as those on £20,000.
It says £30,000 and £50,000 earners will be hardest hit by the 1.25 per cent NI hike, with the increase meaning that they will pay nine percent and ten percent of their salary towards NI respectively
