But look at the rest of the world – in north-east America and Canada, in north Africa, across the Mediterranean, through to south-west Asia, temperatures are very much above normal – in many places by more than 5C, and in parts of northern Canada, by more than 10C.

In a normal British winter - when conditions are mild and soggy - the jet stream lies over northern Europe, at an altitude of between 35,000 to 50,000 feet.
Daily mean temperature anomalies around the world between 1st December and 20th December

Daily mean temperature anomalies around the world between 1st December and 20th December compared with the 30 year long term average between 1961 and 1990

During these grey winters, Britain's prevailing winds come from the west and south west, and bring with them warm and moist air from the sub-tropical Atlantic.

This year a high-pressure weather system over the Atlantic is blocking the jet stream’s normal path and forcing it to the north and south of Europe.

that it has shut down in the past

However, the fact that the Gulf Stream can shut down and has shut down in the past was confirmed in November this year by research published in British science journal Nature. The study looked at the relative abundance in marine sediments of two of the radioactive decay products of uranium: protactinium-231 and thorium-230. The two isotopes are produced at a fixed rate from the decay of uranium dissolved in sea water but protactinium remains in the water for longer than thorium and is transported further by the currents. So analysis of the relative abundance of these two isotopes in the marine sediments of the South Atlantic Ocean indicates the strength and direction of the deep water circulation.

The results suggested that the modern pattern of the conveyor in the Atlantic with a prominent southerly flow of deep waters originating in the North Atlantic, arose only during the Holocene epoch following the last ice age, according to the paper. “This is confirmation of what some previous studies have suggested but not all the previous studies had suggested the same thing so our work provides some reconciliation in this area,” lead author Cesar Negre of the Autonomous University of Barcelona told Reporting Climate Science .Com in November.