Jonathan Blake was only 32 years old at the time, but the meeting the lawyer held with a senior British Treasury minister in 1987 has helped create more millionaires than the UK’s National Lottery.

At issue was a complex structure that Mr Blake had designed to allow the fledgling private equity industry to set up funds in the UK without losing the low-tax treatment it had until then enjoyed offshore. It contained a crucial detail for dealmakers from the worlds of private equity and venture capital: their personal payouts, often eye-watering sums known as carried interest or “carry”, would be taxed as capital gains rather than income.

Tax authorities had objected, saying that if other business and industry leaders paid income tax on their bonuses, private equity executives should do the same.