Gary Hersham has been selling houses to the very rich for decades. At first, £1m was a big deal. Now he sells for £50m, £100m, even £200m. What does it take to stay on top in this cut-throat business?

Ring ring. Gary Hersham’s phone was going, as usual. The super-prime London estate agent blew through the Mayfair office of his company, Beauchamp Estates, scattering employees behind him. As he climbed into the passenger seat of the company car, a Volkswagen Golf rather than his personal BMW, I asked where we were going. “I don’t know!” he said. He found a postcode, and announced it to the driver. Ring ring. Hersham’s mobile has the high-pitched jangle of an old-fashioned telephone at fire-alarm volume. “I didn’t ask you for that,” he roared down the phone as we sat stationary outside his office. “What makes you assume that’s what I was doing? Could I speak to Emily please?” Emily, his fantastic secretary. Ring ring. Someone else was calling. “We’ve got to wait for Marcus!”

Enter, at a trot, Marcus O’Brien, Hersham’s protege: tall, slicked hair, suited and groomed, just 30. (Hersham is 68.) O’Brien had been out for a big dinner the night before, knowable only from his stating the fact: there was no sickly pallor, despite being crammed into the back seat of the Golf, which was now winding its way through Mayfair, past the members’ clubs and hedge funds and townhouses, a neighbourhood in which Hersham has been selling property for 43 years. His agency has sold houses for quantities of money that seem increasingly conceptual as they rise: Belgrave Square (£50m), Caroline Terrace (£60m), Grosvenor Crescent (£100m). Then the ultimate, a career peak in an already elevated range, the most expensive house ever sold in Britain: 2-8a Rutland Gate in Knightsbridge, sold in early 2020 for £215m.