A volcanic outcrop adrift in the cobalt blue of the Tyrrhenian Sea, it seems at first glance a curious place for a crucial post-Brexit summit.

But it was on the island of Ventotene that a group of Italian politicians, who had been interned by Benito Mussolini during the Second World War, hatched a vision of a free, united, democratic Europe that eventually evolved into the EU.

It is that spirit of optimism which Matteo Renzi, the Italian prime minister, will try to tap into when he gathers with Francois Hollande and Angela Merkel on the island off Italy’s west coast on Monday.

For a Europe that has been deeply wounded by Britain’s vote to leave, the choice of Ventotene is highly symbolic – one of the internees was future statesman Altiero Spinelli, who during the darkest days of fascism and Nazism wrote a text now known as the Ventotene Manifesto, calling for a free, federal Europe.

Seventy years on, the three leaders will lay a wreath at Spinelli's tomb as they begin their bid to relaunch the European project in the wake of Britain's vote to leave the EU. They are expected to discuss the implications of Brexit and the timetable for Britain’s departure, as well as the vexed issue of how to promote economic growth whilst keeping within tight budgetary constraints.