It should have been so straightforward: a businessman borrows money from an established property developer in order to fund his latest project, he pays back the loan, and the parties take their share of the profits.

So how have the Candy brothers, Nick and Christian, two of the most high-profile figures in UK business, become embroiled in one of the most salacious court cases in recent years, which began over a £12m loan?

Far from being a straightforward case over a financial disagreement, what has emerged over the nine-week civil trial between the Candys and Mark Holyoake, who borrowed the money, are extraordinary. Claims that the brothers’ relationship is so volatile that their wives do not speak, allegations of tax evasion, and links with Russian gangsters make this one of the most colourful cases the UK business fraternity has ever seen.

Both the reputation of the brothers and Holyoake lie in tatters, with legal bills estimated to be £10m between them.

The saga began around six years ago, when Holyoake, a businessman who formerly owned fish importing business British Seafood, borrowed money from Christian Candy’s CPC Group to help him purchase a London property, Grosvenor Gardens House. He intended to redevelop it into luxury flats and, because the loan from CPC was negotiated at the last minute, CPC would take a hefty share of any future profits.