At a few minutes before 10pm on Thursday night, Michael Spencer was holding his breath. The billionaire stockbroker had booked the elegant fish restaurant Scott’s in London’s Mayfair for his traditional election night party and assembled 200 grandees, including the fund management entrepreneur Martin Gilbert, Ocado chairman Lord (Stuart) Rose and the telecoms tycoon David Ross.

Two years ago, the mood at the same soiree had been — in Spencer’s words — “awful, absolutely dreadful”. His guests had watched with dismay as Theresa May came within a wisp of tossing Downing Street’s keys to Jeremy Corbyn.

With the Tory poll lead thinning in the run-up to this year’s election day, anxiety was coursing through Richard Caring’s restaurant. Four speakers, including former Tory minister Baroness (Virginia)