Anyone who has been to the islands off Scotland’s west coast will be familiar with Caledonian MacBrayne ferries. On a clear still day in summer there can be no better way (for the price of a ferry ticket) to view the beauty of the mountains and islands set against clear blue water. But winter brings a different face to the Sea of the Hebrides, which can be amongst the roughest in the world. Despite this, CalMac as the service is known, keeps going because there is no other way of supplying the islands and carrying back fish and other exports essential to the islands’ economy.

These crossings are frequently not for the faint hearted, but of the 79,203 ferry crossings between January and the end of July this year fewer than 2,000 were cancelled because of the weather. The major problem for these ferries in rough seas is safe docking at the island harbours, often on exposed slipways, which is why most terminals are built in the lee of the islands, away from the full force of westerly gales. CalMac, backed by scientists , is saying cancellations are more likely in future as climate change makes winter storms increasingly violent, and more sweep in from the north-east and the south, making safe docking impossible.