Latest figures released by Government show at least 1.1m construction workers were paid via the Construction Industry Scheme in 2016/17.
This is an 8% jump on the previous year when when 993,000 were paid via CIS and means that 47% of the entire construction workforce is now self-employed for tax purposes.
The surge in self-employment was revealed after a Freedom of Information request by construction union Unite.
It is now calling for root and branch reforms of employment rights claiming the latest figures demonstrate that bogus self-employment is on the rise again.
In 2014 the government introduced measures that barred construction workers operating via payroll companies from being self-employed.
Gail Cartmail, assistant general secretary, of Unite said: “The only way that workers will be treated fairly and decently is by introducing clear rules which ensure that workers are either genuinely self-employed or paid by a standard PAYE method.
“Without such a reform productivity in construction will remain low, accidents and ill health will be high and the industry will fail to train sufficient numbers of apprentices.”