A melting glacier is moving the Italian-Swiss border near one of the world's largest ski resorts

Way up in the snowy Alps, the border between Switzerland and Italy has shifted due to a melting glacier. It is putting the location of an Italian mountain lodge in dispute.

The borderline runs along a drainage divide - the point at which meltwater will run down either side of the mountain towards one country or the other.

But the retreat of the Theodul Glacier means the watershed has crept towards the Rifugio Guide del Cervino, a refuge for visitors near the 3,480-metre Testa Grigia peak. Now it is gradually sweeping underneath the building.

Frederic, a 59-year-old tourist, opens the narrow wooden door to enter the refuge's restaurant, the light flooding in from outside.

The menu is in Italian, not German, and priced in euros rather than Swiss francs. Nonetheless, at the counter, he orders a slice of pie and asks: "So, are we in Switzerland or in Italy?"

It is a question worth asking as it has been the subject of diplomatic negotiations that started in 2018 and concluded with a compromise last year - but the details remain secret.

When the refuge was built on a rocky outcrop in 1984, its 40 beds and long wooden tables were entirely in Italian territory.

But now two-thirds of the lodge - including most of the beds and the restaurant - is technically perched in southern Switzerland.

The issue has come to the fore because the area, which relies on tourism, is located at the top of one of the world's largest ski resorts. A major new development including a cable car station is being constructed a few metres away.

An agreement was hammered out in Florence in November 2021 but the outcome will only be revealed once it is rubber-stamped by the Swiss government. Something that won't happen before 2023.

"We agreed to split the difference,"