One evening last September, more than 100 high-net-worth investors, family offices and private market professionals crammed into an exclusive business members’ club in London and heard the owners of a new company promise to “fundamentally change” the private equity industry.

Truffle Invest, set up by Jason Proctor, a former vice president at private markets specialist StepStone, will give clients access to buyout funds with as little as £5,000.