TORY Chancellor Philip Hammond broke a manifesto pledge yesterday by announcing changes to national insurance contributions for the self-employed.

Self-employed workers earning more than £16,250 a year will see contributions increase from 9 per cent to 10 per cent from April next year, and by a further 1 per cent in 2019, putting an extra £145 million into Treasury coffers over the next five years.

Staff on £32,000 a year pay £6,170 in contributions — jointly with their employer — compared to £2,300 for the self-employed. Mr Hammond said it was not fair that directly employed staff pay more than the self-employed.