Why the UK’s Richest Plumber Regrets Selling His Business to KKR

Charlie Mullins’ father worked in a toy-car factory. His mother cleaned homes. Today, Mullins has a £10 million London penthouse with a view of the Thames. “Tom Jones lives there, if you can believe it,” he says, pointing to the flat above him, where the Welsh singer is a neighbor.

Mullins can credit his dazzling rise to the unlikely intersection of high finance and blue-collar labor. Over four decades he built a successful plumbing business that eventually employed his children and grandchildren. At the end of 2021, he sold his company, Pimlico Plumbers Ltd., to Wall Street giant ...