Snow in London
Londoners could catch the first snow of the winter as forecasters predict possibility of wintery showers for this weekendGetty

Warnings have been issued to British pensioners as an Arctic blast has triggered severe weather alerts across the country. While parts of Scotland and the north of England have been placed on snow alerts, wind warnings have been issued throughout the rest of the country.

Northerly winds have sparked concern over how Briton's pensioners might cope with the sudden freeze. The Met Office has predicted that temperatures will drop significantly this weekend, with London reaching sub-zero temperatures at times.

"We know that the cold is a real health risk for older people," said Caroline Abrahams, charity director at Age UK. "They are three time more likely than younger people to suffer strokes if they do not keep warm."

Age UK has said that it becomes increasingly difficult for bodies to detect how cold it is as people grow older and that the longer pensioners are exposed to the cold, the more they are at risk of heart attacks, strokes, pneumonia, depression, worsening arthritis and increased accidents at home. The Met Office has teamed up with the charity to provide advice for older people on how to handle this weekend's Arctic freeze.

Among the guidelines, Age UK encourages pensioners to protect their health by following the advised temperatures at which different rooms in their house must be set to. The guidelines state that living room temperatures must be set at 21C, while the bedroom should be set to 18C. They have also advised people to keep their windows closed at night.

This weekend's cold conditions could be the first glimpse of the "big freeze" that has been predicted for this winter. While mild conditions could briefly return next week, cooler nights and frost will quickly follow it.

A spokesperson for the Met Office warned: "It's been really well above average so it is going to feel quite different. It looks as though the period of having very mild air for a long time is over."

British pensioners are urged to stay on alert as forecasters have warned of this year bringing the "coldest winter in 50 years". Some experts have feared a repeat of 1963 when the worst winter in history saw temperatures plunge to near -20 in January, blanketing the country with snow for weeks and freezing the River Thames.