Aggressive tax deals by investment banks face “the sanitising effect of sunlight” as a result of a new study, a top tax official said on Friday.

At the Paris launch of a report into structured finance, an esoteric area of investment banking that optimises tax, regulatory and accounting aspects of deals, Dave Hartnett, permanent secretary of Revenue & Customs, said the banking study “lays bare complex structured finance transactions in a way we have never been able to lay them bare before”.