The Conservative Party idea to make firms list foreign workers is worse than Donald Trumo's plan to block Muslims from entering the US, David Cameron's former policy guru has said.
Steve Hilton was scathing about Home Secretary Amber Rudd's suggestion, which provoked uproar after being talked about at the Conservative conference this week.
Ministers might as well announce that "foreign workers will be tattooed with numbers on their forearms," Mr Hilton wrote in the Sunday Times.
The ex head of policy at Number 10 warned that forcing companies to reveal their foreign workers would be "divisive, repugnant, and insanely bureaucratic".
Ms Rudd pleaded with people to not brand her a "racist" after the idea was widely panned, with Labour calling it xenophobic.
The initiative was even attacked by Ukip MEP Roger Helmer, who said: This idea that companies should provide lists of foreigners - if we had suggested that, if Ukip had suggested that, they would have been shouting 'Fascist' up and down the street.
"I personally think that is a step too far."
Mr Hilton also accused Theresa May of being "incompetent and irresponsible" for allowing other countries to think Brexit would cut Britain off from the world.
A Home Office spokesman said: "This is not about listing foreign workers or so-called 'naming and shaming' of companies. The proportion of international workers in a company is one of the pieces of information that companies may be asked to provide to the Government.
"This information will not be published. This already happens in the US and is one of several proposals we will be consulting on as part of our work to ensure that companies take reasonable steps to recruit at home before looking to bring in workers from abroad.
"The purpose of having a consultation is so that we can listen to business and use that feedback to inform our decisions".