When Hurtigruten ordered two state-of-the-art ice-class exploration cruiseships at Kleven Verft in 2017, there was much fanfare about their green credentials.

As the first cruiseships to use an electric propulsion system — a combination of battery and fuel power — the newbuildings were dubbed the “hybrid cars of the seas”.

The Norwegian ferry company is suggesting the 530-passenger Roald Amundsen and Fridtjof Nansen could revolutionise shipping in the same way the Toyota Prius has transformed the car industry.