Heavy snow is still causing major disruptions in the UK with more than 100 motorists stranded in Devon, according to reports.

Firefighters from Devon and Somerset Fire Brigade are at the scene of what is being described as "a major incident" on the A38 near Exeter.

Forecasters are now warning there is more snow on its way.

The death toll of the week's wintry blast also rose as it emerged two walkers died after venturing out in icy conditions in the Lake District.

But as travellers reeled from another day of airport hold-ups and train and bus service delays, forecasters warned southern regions faced a fifth consecutive day of chaos.

The snow is heading south with London, Dorset, Somerset, Hampshire, Berkshire and southern Oxfordshire expecting coverings of up to 6in.

Weather forecaster Paul Knightley said plunging temperatures on Friday night would make Britain's roads even more dangerous over the weekend.

He added: "There is no sign of the let up as far as the snow and ice is concerned.

"The only difference is that the snow is likely to be wetter than what we have had earlier in the week.

"Areas such as London may not see the snow settle as thick."

With temperatures dropping as low as minus 8C, councils are perilously close to running out of salt and grit with some forced to ration its use.

Councillor Paul Bettison, chairman of the Local Government Association Environment Board, said eight councils have had to "prioritise" their remaining salt stocks in order to focus on the most important roads.

He added: "If that fails to deal with any issue, then councils will talk to the Highways Agency to look for further supplies."

Some councils said they were now using salt only on major routes and Britain's biggest salt supplier, Cheshire-based Salt Union, said staff were working around the clock but still could not meet demand.

© Independent Television News Limited 2009. All rights reserved.