The Sunday Times said Sir Jim Ratcliffe (inset), a prominent Brexit supporter, has been working with international accountancy firm Pricewaterhouse Coopers (PwC) to help with the tax plan. Sir Jim, knighted less than a year ago for services to business and investment, is chairman and chief executive of the Ineos chemicals group - which runs Grangemouth Refinery.
According to reports, he would legally share with two senior executives between £1bn and £10bn tax-free. This plan would leave the Treasury short of between £400m and £4bn a year.
It is understood PwC has consulted its public interest body over whether it should refuse to help with the scheme or drop the Ineos account over potential damage to its reputation.
PwC told The Sunday Times: “PwC can confirm that it did not consider there was any reason to terminate its relationship with Ineos.”
Ineos said: “Ineos and its owners always fully adhere to all tax legislation.”