Reasons vary for the western world’s political convulsions, but one photograph leaves little doubt how quickly its ruling elite has changed beyond recognition.

The smiling faces at a summit in Hanover in April represented the four largest European economies and a United States then confident of political continuity. But the resignation of the Italian prime minister, Matteo Renzi, on Monday now means all but one of the G5 leaders will leave office under very different circumstances.

David Cameron was perhaps the clearest casualty of a populist rebellion against the establishment, driven from office after losing a referendum that became a surprise plebiscite on the status quo. Barack Obama was leaving office in January whatever happened but risks seeing his legacy destroyed by a similar backlash that elected Donald Trump.

Like Renzi, François Hollande said last week that he would not seek re-election as French president for more complex reasons – not least the fact that he would probably lose by a landslide – but both leaders are struggling to convince economically struggling electorates wary of incumbents.

Only Angela Merkel, who announced last month that she would seek a fourth term as German chancellor, could be at a future meeting of the G5.