The introduction of IR35 has caused contractors to come together over the controversial legislation, according to a special report by ContractorCalculator.

IR35 was proposed in the 1999 Budget of the then Chancellor Gordon Brown to target ‘disguised employment’ - workers who receive payments from a client via their own company. These payments are not subject to NICs as they can be treated as dividends, and workers can also save tax by splitting ownership of the company with family members to place income in lower tax bands.

Chief executive of ContractorCalculator, Dave Chaplin, says: “It is the massive burden of business taxes and regulation, like IR35, that is now holding back the UK’s economic growth.

“Before IR35, contractors did not have representation or any sense of group identity.

“But when the government introduced this  poorly thought-through and appallingly implemented piece of legislation, with no genuine consultation or impact assessment, contractors for the first time banded together to fight the assault on their livelihoods.”