Hampstead Heath, December 2010 by Marcus Fallon

It’s the third hard winter in a row, following two decades of relatively mild weather. Should the government invest in new technology to reduce the impact of severe winters? How many snow ploughs should the country have?

Philip Eden, Vice President of the Royal Meteorological Society, explains that cold winters in Britain are caused by a weak jet stream and often come in batches.  If the jet stream meanders southwards, Spain gets the Atlantic depressions instead, leaving the UK exposed to winds from the north, which bring the snow and low temperatures. Long term records show that clusters of cold winters occur with relative frequency: looking back at the last 50 years, 1962-65, 1968-70, 1978-82, 1985-87, and, to a lesser extent, 1995-97.

His verdict: no need to panic and stock up on the snow ploughs just yet.