If new proposals to harmonise self-employed taxation with employed taxation are adopted, contractors could see their tax bills soar, according to reports.

The Mirrlees Review has put forward a key proposal which intends to tax those who are self employed equally with those who are employed, according to Contractor Calculator.

As well as increasing tax for contractors, this could effectively see the end of IR35 as the proposals make it redundant.

In addition, under the review, the basic tax band could increase to 34 per cent with the higher one at 66 per cent due to the combination of National Insurance and income tax, heaping yet more costs on contractors.

IR35 was introduced in April 2000 and means that some contractors' can already be taxed as if they are the employees of their clients.

However, as the review proposes that all contractors should be taxed as if they are employed by another party, it seems that if the measures are adopted, this will spell the end for IR35.