The growth in self-employment in the UK could cost the Treasury an additional £3.5 billion a year by 2021 due to generous tax breaks, reports the Belfast Telegraph, with data from the Institute for Fiscal Studies. With the growth of the gig economy, the proportion of people who work for themselves is expected to increase. As of now, the tax paid on earnings for an employee is higher than that of a self-employed worker. The Institute of Fiscal Studies is calling on a “level playing field” so that self-employed workers and company owner-managers pay at the same rates as employed workers.