A year ago Carlo Calenda ran in European parliamentary elections in Italy under the slogan “We are Europeans”, a rallying cry to defend his country’s place in the EU at a time of rising nationalism.

Now even Mr Calenda, a 46-year-old former minister and Italian permanent representative to the EU, is experiencing a crisis of faith in an idea he has spent a lifetime fighting for. 

“This is an existential threat, I am not sure if we are going to make it,” he says. “You have to consider my party is one of the most pro-European parties in Italy and I now have members writing to me saying: ‘Why do we want to stay in the EU? It is useless.’”