In early December 2017, years before his empire collapsed, financier Lex Greensill needed a quick decision. The businessman was looking for insurance cover and had turned to a new operation backed by Australian insurer IAG.

The insurance would cover a financing deal between Greensill Capital and part of entrepreneur Sanjeev Gupta’s global steel operations. And Mr Gupta had mentioned Greg Brereton, an underwriter at an insurance agency then half-owned by IAG, was interested in offering cover, according to an email from Mr Greensill to Mr Brereton.