The billionaire banker whose finance firm has collapsed and who is now at the centre of a lobbying scandal involving ex-Prime Minister, David Cameron.

Alexander "Lex" Greensill, grew up on his family’s sugar cane and melon farm in Queensland, Australia. After moving to the UK, he went into investment banking, founded a supply chain finance empire - complete with private jets - and, under David Cameron, secured a role in Britain’s Conservative-led Coalition government. After leaving office, the ex-PM became an adviser to the firm – Greensill Capital - which went bust last month, putting at risk 50,000 jobs worldwide.

Mark Coles charts the rise and fall of the farmer’s son who, so the story goes, began his finance company to help small firms get paid more quickly by big businesses.

Researchers: Matt Murphy and Stefania Okereke Producer: Sally Abrahams Editor: Richard Vadon