For John Caudwell, the giveaway was the bespoke diamond ring. One of Britain’s wealthiest men had decided to put his investment in a diamond retailer called Vashi to the test with some mystery shopping. “I asked them to design a ring for me.

It was terrible,” says the founder of Phones 4u. “They claimed to be experts in design but the customer service was poor – it was slow, not effective and not a good design.” The billionaire decided to dig deeper, paying a visit to Vashi’s flagship London store in Covent Garden.

He stood outside, counting how many shoppers went in, and says that from this snapshot he could not understand the company’s sales claims: “It just didn’t add up.” Caudwell had already invested £1m in Vashi, after its diamond-trader founder, Vashi Domínguez, wooed him during the pandemic – and came with a promise of donating, also promising to donate to his charity, Caudwell Children. (Caudwell claims Vashi’s charity donation was never forthcoming.

) He says he was later asked for a further £2m, but “they became irritable when we wanted a lot more detail” and he did not stump up. Now the tycoon is among a clutch of high-profile investors nursing losses after Vashi collapsed, leaving a trail of financial wreckage behind it – and questions over the whereabouts of diamonds and jewellery once valued at £157m. Over more than a decade, the charismatic jeweller had wooed some of the UK’s best known entrepreneurs as shareholders – fr.