Coldest December on record puts brakes on start of the big getaway

December 2010 is "almost certain" to be the coldest since records began in 1910, according to the Met Office.

As people trying to make an early festive getaway faced treacherously icy roads and cancelled flights, and retailers warned that up to four million parcels may not be delivered in time for Christmas, forecasters said that this month is on course to beat the previous coldest, which was December 1981.

Weathermen suggested that some parts of the south of England could see further snowfalls of up to 10 inches (25cm) today. Blizzards of heavy snow and ice are expected to bring further disruption over the next two days to roads, rail and flight services, particularly at Gatwick, as well as to retailers on the busiest shopping weekend of the calendar. Police in Northern Ireland – where conditions are said to be the worst in 25 years – and parts of Scotland were warning people against non-essential travel.

Deep drifting snow closed main roads across the Grampians, while major accidents were reported in Glasgow, Aberdeenshire and Kent, causing four deaths. A 17-year-old boy from Bislington, Kent, was killed when his car left the road.

The day was marked by two incidents unusual even in such extreme conditions. In Sheffield, a man was stabbed in the neck during a snowball fight. The 19-year-old confronted a group of youths throwing snowballs "aggressively" at passers-by, police said, after which he was "kicked, punched and stabbed in the neck with a sharp object, possibly a broken bottle". The man required surgery but was later discharged. In Leicester, police discovered a large cannabis factory after noticing that its hothouse growing conditions had melted the snow on its roof. Flights were suspended at London City Airport, Belfast International, Exeter, George Best and City of Derry airports, and further cancellations are expected at Gatwick, Heathrow and Stansted over the weekend; easyJet has cancelled all its flights in and out of Gatwick airport between 6am and 10am today. Further road closures are expected across England and Scotland as drifting snow and bad ice will lead to "the worst driving conditions imaginable, even for experienced drivers", the AA warned. "The issue is that traffic will generally be busier nationwide as there will be more long-distance traffic as people start to head off for Christmas and the retail distribution network clears the backlog," said a spokesman. The breakdown service expected to have received around 18,500 calls by the end of the day.

The Met Office said the average mean temperature for the first two weeks of this month was -0.7c. Temperatures are likely to drop into "the minus teens" in some parts of the countryside, with lows down to -8c in cities. The coldest average for this time of year – recorded in December 1981 – was 0.2c. "If it remains as cold in the second half of the month as it has been so far, then it is likely that December 2010 will indeed by the coldest since the national record began in 1910," the Met Office said.

Overnight temperatures in Northern Ireland were expected to drop as low as -10C. The Met Office issued an emergency flash warning for heavy snow in three Northern Ireland counties, Antrim, Down and Londonderry. Extreme precautions were being taken in the West Midlands as the ambulance service urged people across the region not to travel or go outside unless absolutely necessary.

The wintry weather is set to take its toll on the weekend sporting fixtures as a number of games were postponed, with the Scottish Premier League and English lower league divisions worst hit. Children revelled in an unexpected day off as 800 schools in Wales, 500 in Scotland and 600 in Northern Ireland closed, primarily citing broken boilers or health and safety fears.

The Government has warned that the winter oil situation could become "very serious", with some homes having to wait as long as four weeks for fuel to be delivered. Downing Street played down suggestions that oil may have to be rationed over the winter.