With sub-zero temperatures and snow fall expected to hit large swathes of the UK from the end of this week, bookmakers have slashed the odds on a white Christmas.

Met Office forecasts for wintry showers and icy weather going into December have prompted William Hill to change its own outlook on the likelihood of snow on December 25.

October and November has been unseasonably mild but things are set to change this week and a cold snap is said to be looming. Longer range forecasts now warn of wintry showers and widespread icy conditions from the start of next month with temperatures in some areas at risk of falling to -11.

The Environment Agency is also warning of a wetter than normal end to this winter - with the worst of the rainfall expected after Christmas in January and February and bringing with it a greater risk of flooding.

The popular pastime of betting on a white Christmas, which was instituted by William Hill, traditionally required a single snowflake to fall on the MET Office operations centre in London.

But with that building no linger in existence, and national weather services now located in Devon, all that is needed to declare a white Christmas is the sight of a snowflake falling in the 24 hours of December 25 at one of 12 major UK airports.

The UK has not seen snow settling on the ground on Christmas Day since 2015 when it was recorded at a tenth of all weather stations.

Leeds Bradford Airport, which is more than 700ft above sea level and holds the record for being the highest airport in the UK, is 3-1 favourite now for a White Christmas, closely followed by Scottish duo Edinburgh and Glasgow at 10-3 and 7-2 respectively.

With snow-filled Christmas-card scenes now more likely in northern areas, Liverpool (7-2), Newcastle, Manchester, and Birmingham (all 4-1) have all seen a significant tightening of their odds in recent days.

William Hill spokesperson Rupert Adams said: “While we’ve enjoyed a relatively mild November to date, we now look set to welcome freezing temperatures in the coming days. Forecasters are already calling snow showers for the tail end of this week, and with most of the forecasting tools at our disposal pointing to more of the same for early December, we had no other option than to cover our backs.”

Belfast (9-2) and Dublin (6-1), join the likes of London, Bristol and Cardiff as the least likely - but even the worst case, Cardiff, still has an 8-1 chance, the shortest-priced outsiders since 2017, which was the last true white Christmas in the UK - with 11 percent of weather stations recording snow falling.