Very heavy snowfall is predicted in southern England after freezing conditions brought more chaos to Britain's transport network today, shutting airports and disrupting train services.

The Met Office said temperatures fell to as low as minus 15 C overnight and warned that as much as 40 cm (16 inches) of snow could fall in some areas as the weather front spreads south.

Severe weather warnings are in place across Scotland, northern, central and western England after heavy snow and problems caused by widespread icy roads.

The forecaster said even more heavy snowfall was expected further south and in London later today and tomorrow, with Hampshire, Oxfordshire and Berkshire predicted to be worst hit.

"A period of exceptionally heavy snowfall is expected with accumulations of 15-30 cm and perhaps in excess of 40 cm," the Met Office said.

"This is expected to cause widespread disruption to the transport network and could lead to problems with power supplies."

Manchester Airport was closed until 1 p.m. because of heavy snow, and flights were being cancelled at Leeds Bradford, Liverpool and Glasgow Airports.

Many train services across Britain suffered cancellations and delays with severely reduced services on the East Coast mainline from Scotland and northern England to London.

Motorists were advised to take care if they had to travel, and the Highways Agency said "continuous salt treatment" was being carried out at high-risk areas.

The AA said it expected today to be its busiest day ever for breakdowns with 25,000 call-outs.

High demand for gas prompted Britain's network operator National Grid on Monday to warn consumption may have to be cut, which encouraged producers to increase flows into Britain.

The Met Office has said it expected the freezing conditions -- caused by winds coming from the north and east instead of the more usual west and southwest -- to continue into late January after one of the chilliest Decembers on record.UK Met Office issues